Stocking aquarium

Best Ways To Stock A Five-Gallon Fish Tank

Last Updated August 27, 2021
Stocking Five Gallon Fish Tank

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If you’re thinking about setting up a 5 gallon (18L) aquarium, it’s easy to get confused by the conflicting information spread around the internet and by aquarium stores. What are the best fish for a five-gallon fish tank? How many fish should you get? Can you put plants in?

Keep reading for everything you need to know about stocking and maintaining one of these small fish tanks!

How to stock a 5 gallon aquarium?
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Five-gallon aquariums are among the most popular tank sizes. Not surprising, as they are small and you can easily fit one into pretty much any room. Is a five-gallon a good choice, though?

A five-gallon tank or cube is the smallest size aquarium that can actually hold fish. Any smaller than this and you’ll encounter difficulties keeping a stable cycle and not providing your stock with enough room to swim. Even the smallest fish need space to move and explore!

A quick look on the internet seems to reveal plenty of options for your five-gallon. Some sites list many species as suitable for a tank this size, but are they really? Although a well-maintained five-gallon aquarium can make a great addition to your home (especially when densely planted), it does limit your choices of fish. Is that bad?

I say no! Even though there aren’t many different fish species that will thrive in a five-gallon aquarium you can still set up a lively and entertaining tank. My favorite choices for an aquarium of this size are invertebrates.

We’ll lay out the do’s and don’ts of stocking a five-gallon fish tank below – let’s start with the don’ts.

Fish to avoid

To prevent confusion, the list below contains some fish species that are often recommended as being suitable for five-gallon setups while they would actually do much better in a larger tank. They are too active, grow too large or are unable to handle unstable water quality.

When stocking your five-gallon, be sure to avoid them! Bolded names lead to a full care sheet with more information about the particular species.

To prevent confusion, the list below contains some fish species that are often recommended as being suitable for five-gallon setups while they would actually do much better in a larger tank. They are too active, grow too large or are unable to handle unstable water quality.

When stocking your five-gallon aquarium, be sure to avoid the offenders on this list! Bolded names lead to a full care sheet with more information about the particular species.

Even tiny fish like dwarf Rasboras need more than 5 gallons to thrive.

  • Fancy goldfish – need 20 gallons (75L) per fish. Additionally, since these guys are highly social fish, it’s inhumane to keep just one. Most keepers recommend 20 gallons plus 10 (38L) for each additional fish. However, given their heavy bioload, it’s a much better idea to aim for 20 gallons per fish instead.
  • Common goldfish – exclusively pond fish. These fish get big – up to 14 inches (over a foot/35 cm)! Given their size, and the fact that they need at least 40 to 100 gallons (100 to 380 liters) per fish, it’s no wonder why common goldfish never do well in five-gallon setups!
  • White cloud mountain minnow, celestial pearl danio, zebra danio – active schooling fish. Any schooling fish need lots of companions to reduce stress. In a five-gallon tank, there’s just not enough room to safely do this. Additionally, they’ll lack the space they need to swim.
  • Dwarf pufferfish – sensitive to water quality fluctuations and boredom. These little guys do best in 10+ gallons (38 liters) with lots of hides and decorations to explore. If you want to get a single fish another puffer friend, you’re realistically looking at 15+ gallons.
  • Neon tetra, cardinal tetra, black neon tetra – active schooling fish. Just like with the white cloud mountain minnow, (neon) tetras become stressed when kept in groups of less than 8 individuals. If you really want to see these beauties at their best, set them up in a large (and long) tank with plenty of companions.
  • Guppy & Endler’s guppy – grow too large. Not only do they get bigger than you’d think they do, but they breed like crazy. It doesn’t help that even if you buy all females, they may be pregnant right from the pet store or breeder. The small space also doesn’t allow for the females to escape males constantly harassing them to breed.
  • Apple & mystery snail – grow too large and produce a lot of waste. People always underestimate just how many waste snails produce, which you will definitely discover while maintaining the filters. To make life a bit easier on yourself, aim for bigger setups. In a small tank, stick to Nerite snails instead.
  • Rasbora species – active schooling fish. Again, it should come as no surprise that even the tiniest of rasboras, such as mosquito rasboras, still do best in large groups and spaces. More common species, like harlequins, deserve bigger and better for the overall health of the fish.
  • (PygmyCorydoras – all Corydoras species are too active and/or large, schooling. Pygmy Corydoras, often wrongfully recommended for nano setups, are also very sensitive to water chemistry. Since five-gallon aquariums tend to have less stability when it comes to water chemistry, any little change can spell disaster for the pygmies. Although a lot of people tend to recommend getting just one Corydoras as a “cleaner” fish, don’t be fooled! They need others of their species and these fish can’t survive on algae alone.

As you can see above, many of the popular fish species that are often recommended for five-gallon setups are actually not the best idea, but don’t despair!

Suitable fish & inverts

There are a few fun fish and invertebrates that will do wonderfully in a tank of this size. However, just remember that you must cycle your tank! In a 5 gallon aquarium, it’s easy to mess up the water chemistry, which can prove fatal to the inhabitants before you even know there’s anything wrong.

Below are examples of suitable critters for stocking five-gallon tanks.

  • 1 x Betta fish (full care sheet here). A single Betta fish does well in a five-gallon tank that is cycled and has plenty of hiding places. You may think that it’s a lot of space for a single fish, but once you see a Betta make full use of every inch of its new home, you’ll never go smaller again! 
  • If you want to branch out and try something different, you can also do other species of Bettas, such as Betta smaragdina, Betta mahachaiensis, Betta imbellis, or Betta siamorientalis. Just remember that these fish do best on their own as well and should not be kept in pairs except for breeding.
  • 2 x Least killifish (Heterandria formosa). While you can keep a pair of least killifish in nano setups, just remember that they may breed. In such a case, you’ll need to have larger spaces available for growing out of the fry.
  • 10 x Cherry shrimp* (full care sheet here). Even though cherry shrimp can thrive in five-gallon tanks, they are still very sensitive to changes in the water so stay on top of your water quality! You can start with ten individuals.
  • 2 x Dwarf crayfish* (full care sheet here). Dwarf crayfish are my favorite for stocking nano setups because they are small but pack plenty of personalities!
  • 5 x Thai micro crab (Full care sheet here). Thai micro crab are perfect for many nano setups that have lots of hiding places and peaceful inhabitants. They easily get along with shrimp and snails.
  • 5 x Nerite snail or assassin snail. It’s important to remember to do one or the other since assassin snails hunt other snails!

*Or other dwarf shrimp species such as orange sakura, yellow shrimp, blue fairy shrimp, etc., see this thread for more options. When going for dwarf crayfish, be sure to choose one of the smaller species such as Cambarellus diminutus and not the larger CPO (Mexican dwarf crayfish).

Many of these species can be combined as their bioload is relatively small. You can easily add a few shrimp or snails to pretty much any setup, although if you decide to go for a Betta it’s a good idea to have a plan B. It depends on the individual fish whether they have a taste for these inverts or not.


Although your options when it comes to fish are limited, five-gallon aquariums are perfect as planted tanks. There are plenty of plant species that stay relatively small and don’t require much maintenance. The species on the list of nano aquarium plants might prove helpful here!

Setting up and maintaining a lovely green aquascape is not as difficult as many aquarists think and nothing will make your stock happier than a natural environment with plenty of hiding places. A well-maintained planted tank will really brighten up any room and bring a tiny piece of nature into your home. Even in such a limited amount of water, you can truly set up your own little ecosystem.

Keep in mind…

The best way to stock nano tanks is still subject of a heated debate on many aquarium forums and websites. When picking a stock yourself, try to keep in mind that just because a fish survives, this is no guarantee it’s thriving.

Be honest with yourself about what’s the best for your fish and remember that understocking is always better than overstocking and choosing fish responsibly can save you a lot of heartache, trouble and money in later stages.

If you still have questions about stocking your five gallon aquarium or if you want to share your own experiences, be sure to leave a comment below. Happy fishkeeping!

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  • Reply Mama Bear July 10, 2021 at 5:58 pm

    I have a 5 gallon tank and I have a glofish shark and two glofish tiger Barb’s in mine with a couple of glofish rocks and decorations. As long as I keep my tank cycled I have not had a problem. Plus they are fun to watch at night under the blue light as everything in my tank glows

    • Reply Jennifer Doll July 13, 2021 at 10:09 pm

      Even though they might look happy, they’re not thriving. Those fish need a bigger tank.

  • Reply Prudhvi G June 6, 2021 at 11:33 am

    Hi I am Very New to this Aquarium Hobby So I really Need Your Help
    So I Got a 6 Gallon Tank Recently Dimensions Are : 15.74Inches x 9.05Inches x 9.84Inches
    and I also Got A Good Internal Filter and the Temperatures are also All right as I Live in India my Water Temperature is around 26-28Celcius.
    And I Wanna Buy A Beautiful Looking And Hardy Fish.
    So can you suggest Me Fish Please
    Which Fish do you Suggest Me?
    And Thx a Lot

    • Reply Jennifer Doll June 11, 2021 at 3:44 am

      Hi Prudhvi!
      Your best bet for a hardy, beginner fish in 6 gallons is a betta fish. Everything else is a little more experienced for that tank size.

  • Reply Brianna June 4, 2021 at 2:26 pm

    Hello, I just recently bought a 5 gallon cube tank that I am going to put my betta in. What other fish can I include and how many? Also, what temperature should I have the tank at?

    • Reply Jennifer Doll June 5, 2021 at 2:50 am

      Hi Brianna!
      A 5 gallon is good for a betta and 1-2 snails. Some hobbyists have luck with shrimp as well, but if you’re a beginner, I wouldn’t recommend it (those shrimp can really be expensive and sensitive to changes in water parameters!).
      The tank should always be between 77-80 degrees Fahrenheit.

  • Reply Jason April 1, 2021 at 8:42 pm

    I am about to set up a well planted 5 gallon tank, and I’m wanting to have a betta, 2 amano shrimp, 1 nerite snail, and 1 kuhli loach. Will this work?

    • Reply Jennifer Doll April 8, 2021 at 9:53 pm

      Hi Jason!
      A 5 gallon planted betta tank will look great and your stocking plan should work for the most part. However, kuhli loaches are pretty active fish and do best when in groups. A 5 gallon tank is simply too small to make your kuhli feel truly at home. Everything else is good, though!

    • Reply Vladimir Milojkovity May 5, 2021 at 1:47 pm

      Hello Mari,
      I would like to get some advice. After reading this article about setting up 5 gallon tank I made up my mind. I am experienced aquarist. But I never had small aquarium like 22 litre as I am planing to set up. I was thinking to put in, except some live plants and few cherry shrimps, 3-4 female bettas, which I saw in the store. I somehow find aquarium without fish not that interesting, but I would like to have more then 1 fish in it, so I thought female bettas will be more suitable, but only if they can work with cherry shrimps, which I also find attractive and I think instead of snails to put them. Is this a good choice? Will it work? Thank you for your answer.

      • Reply Jennifer Doll May 6, 2021 at 4:25 pm

        Hello Vladimir!
        A smaller tank isn’t that much more difficult than a larger tank if you’re willing to put in the work, though as you said, you’re that much more limited for what you can do.
        Your plan sounds great, except for the bettas. Unfortunately, with a small tank, you’re going to be limited with fish that you can keep. 3-4 bettas need at least 20 gallons (75.7 L). Betta harems are pretty tricky to set up in the first place and definitely need all the space that they can get for aggression.
        The best choices for your tank would be one male OR one female betta, least killifish, or just invertebrates. Unfortunately, there are not too many species of fish you can keep in that size of a tank. That doesn’t mean that it will be boring, though!

  • Reply Mat January 24, 2021 at 7:18 pm

    I want to get a 5 gallon tank and stock with shrimp. Can I mix cherry/crystal/ghost shrimp? Also, how many total shrimp should I have in the tank, and is there an ideal amount of each? I also wonder if you know of a good source of information regarding plant planning for the setup I am describing. Thanks!

    • Reply Jennifer Doll January 29, 2021 at 5:32 pm

      Hi Mat!
      You can mix the ghost shrimp with both cherry and crystal shrimp, however, they have a tendency to eat offspring of other species. Crystal shrimp tend to be much more sensitive to water parameters than cherry or ghost shrimp; their preferred conditions are also slightly different in general, and it’s enough to stress out and even kill your cherries. I would recommend picking one or the other and doing a species-only tank. Remember that species of the same genus can interbreed, so avoid mixing similar shrimp!
      As for how many you can have in a 5 gallon tank, you can have a decent amount of any of them. Because of their high price, hobbyists usually buy 3-5 shrimp and let them breed on their own. As long as your water parameters don’t start to fluctuate and the tank doesn’t look cramped for space, then it is hard to have too many shrimp.

  • Reply Philana November 6, 2020 at 12:58 am

    Can I put some nerite snails in a five gallon tan. Also what else would you recommend make tank is more tall then wide btw.

    • Reply Jennifer Doll November 6, 2020 at 8:01 pm

      Hi Philana!
      Nerite snails are some of the best snails to get for a tank since they need brackish/saltwater to reproduce. This means that you won’t have any problems with them overpopulating your tank. For a 5 gallon, I would get maybe 1-2 nerite snails at the most. You want there to be enough natural algae for each one to have.
      Unfortunately, 5 gallons isn’t too big to begin with, and being tall will make stocking even more difficult. The best stocking would probably be one betta fish with one nerite snail; being a tall tank, make sure that your betta is able to swim to the surface of the water without getting tired. If you see your fish struggling, you might need to add plants/other resting spots near the top.
      The other option would be to make this tank a shrimp-dedicated setup. There are several types of shrimp, like Amano and cherry, that can completely bring an aquarium to life! You can also add live plants and watch the shrimp graze on algae. Though small, they’re definitely an underrated addition.

      • Reply Johnie February 22, 2021 at 8:02 pm

        I was wondering in a 5 gallon tank instead of just having only one fish like a betta is there anyway I could have more than one fish in a tank and what fish would that be if possible?

        • Reply Jennifer Doll February 22, 2021 at 10:48 pm

          Hi Johnie!
          5 gallons is, unfortunately, not a lot of space for fish and the betta/shrimp/plant combination is always the most recommended setup. That doesn’t mean that you can’t have a showstopping tank though!
          Some fish you can keep in a 5 gallon are endler’s, chilli rasboras, and scarlet badis; if you really want to test your aquarium skills, you can always make your 5 gallon a mini saltwater reef. Remember that your water parameters will fluctuate much more than a larger tank would and to make sure that the fish you get don’t need to be in larger schools.

  • Reply Brian April 14, 2020 at 2:12 pm

    I’m looking to start a 5 gallon freshwater aquarium. It will mostly be shrimp. But, I would like to add either a dwarf crayfish, micro or pom pom crabs, and or nerite snails. Is there a combination where I can add two or more with the shrimp? I plan on having plenty of plants and hiding areas.

    • Reply Jennifer Doll April 17, 2020 at 8:31 pm

      Hi Brian,
      5 gallons isn’t a whole lot of space to play with, but some people make really beautiful nano systems. I think the key to these tanks is simplicity but with diversity. I personally have not had good experience with crayfish, so I am a little biased and tend to favor shrimp-only planted nanos. A lot of people like to keep cherry shrimp with pom pom crabs, though there is always the chance that your crab could go for one of the shrimp. For a 5 gallon tank, I would go for maybe 2 crabs and maybe 2-3 shrimp. Honestly, snails will probably come in on any plants you buy anyway, so I think that space would be more interesting with crabs and shrimp instead.
      I hope this helped!
      Happy crab-keeping!

  • Reply Lillie March 20, 2020 at 5:40 pm

    Hey on the dwarf crayfish you say they’re suitable for a 5 gallon but when I look on the provided caresheet, it says I need an 8 gallon. I’m very confused due to this. Could someone clear this up?

    • Reply Jennifer Doll March 20, 2020 at 8:59 pm

      Hi Lillie,

      It is a little confusing, but the smallest crayfish species, such as cajun dwarf crayfish, are suitable for 5 gallons and slightly larger ones like the CPO crayfish need a little more room, that’s why it’s set to 8. So the range is 5-10 gallons with each tank minimum being dependent on the species you’re looking to buy. Sorry that is a little confusing! If you have questions about a specific species, I can help even more.

      Happy crayfish keeping!

  • Reply Whitney August 28, 2019 at 10:34 pm

    I have a five-gallon tank that I am wanting to use for betta. I have read else wear that you can have snails and betta together, and the snails help with bio cycling. Would this work?

    • Reply Mari September 1, 2019 at 4:54 pm

      Hello! It’s true that you can keep Bettas with some types of snails. In a five gallon you could consider a nerite snail or an assassin snail, since their bioload is not so big. The snail won’t help with cycling nor will it keep your tank clean like some aquarists think, but they’re fun to watch doing their thing scraping the tank walls 🙂

  • Reply Niki July 23, 2019 at 7:57 pm

    Hi- I have a 5 gallon marineland tank. I currently have an Amano shrimp and an olive horned Nerite snail in there. I have 2 Marimo balls and 3 other plants in the tank. Can you recommend some fish that would be good in this particular set up. I love the nano fish and have thought about a betta- but I would like some other ideas. I want something active and colorful. Thanks in advance.

    • Reply Mari July 24, 2019 at 4:47 pm

      Hello! What I would do personally is actually some Cambarellus diminutus, texanus or one of the other mini species. They are actually more fun than a fish would be in many cases with their silly antics. Additionally, aside from the species on this list there are no fish that can be kept in a tank this size in my opinion. It’s really only Bettas.

      Good luck!

  • Reply Jay November 18, 2018 at 9:53 pm

    Hello Mari. Thank you for this very insightful article. I currently have a 5 gallon with a RCS, nerite snail and ramshorn snail, but am planning to add 2-3 least killifish and some Thai micro crab. How much of these animals on the list can I ideally stock while keeping all of the animals healthy and thriving? I wanted to ideally add more RCS as well and possibly the dwarf crayfish. Thank you again!

    • Reply Mari November 20, 2018 at 5:54 pm

      Hi! I think with your current plan you might be overstocking the tank a little. I would skip the fish here and stock it with RCS, the crabs and the snails. I’d skip the dwarf crays as well in this case or swap the crabs for crays. Don’t worry about the tank being boring; with this stock it’ll be a joy to watch! 5 gallons is just really tiny and it”s best not to overdo things.

      Good luck 🙂

      • Reply Jay November 22, 2018 at 10:37 am

        Hi again! I didn’t mention it beforehand, but does it make a difference if my tank is heavily planted with a filter (the one that comes with the Fluval Spec V to be exact)? Asking because I’m really looking forward to the killifish as an addition to the tank (around 3-4), in hopes of stocking the other animals around them. If my nerite snail moves out could that possibly give more room for the micros along with the RCS?

        • Reply Mari November 22, 2018 at 5:08 pm

          I was already factoring in a filter, since that’s a must for all aquariums. Plants help but you still really have to watch your stocking plan since things can go south so quickly in small set-ups. What you can do is go with the killies and the RCS, but if that’s what you want then I’d skip the rest. Snails especially produce quite a bit of waste.

          If you have room you can always set up another 5 gal for the snails and crabs or crayfish, maintaining two doesn’t take much more work than one.

          Hope that helps! 🙂 Good luck, sounds like a fun project you’re working on here.

        • Reply Jane Doe May 9, 2019 at 7:36 am

          If you plan to keep Least Killifish with RCS, you’ll need to HEAVILY plant your tank to create hiding spaces for your RCS or the fish will gang up to bully and eat them. Happened to me after I removed plants.

          • Mari May 13, 2019 at 3:47 pm

            Really?! I wouldn’t expect such small fish to go at the RCS so hard, especially considering the fact that their larger guppy cousins do relatively okay with them. Good to know 🙂

  • Reply gaby March 31, 2018 at 3:49 am

    hey its me again, I just wanted to say thank you so much for all the help you have given me and im here also to report that i have finally rehomed my guppies and Bristle nose. Also just one last favor that i need, i was wondering if you could maybe do a caresheet for the killifish and also what is in your opinion the best tank to get. Thank you!!!ga

    • Reply Mari March 31, 2018 at 2:05 pm

      Hey! Thank you for the update, I love getting them especially if they’re positive! As for Heterandria formosa, I don’t have much personal experience with them so I’m not sure if I’m the right person to do a caresheet on them, but there is one on Seriously Fish that seems pretty good 🙂

      As for tanks, it doesn’t matter too much and totally depends on what you want from it – although I do recommend a rectangular rather than a square one if you’re interested in keeping active species like these “killifish”. They like having some swimming room.

      Good luck!

  • Reply Gaby January 31, 2018 at 2:39 am

    Also, if I get 2 to 3 killifish how many shrimp or cray fish can I put in as well. What other kinds of shrimp can I put in that are ok but attractive. Thank you

    • Reply Mari January 31, 2018 at 11:07 am

      If you get 2-3 least killifish (Heterandria formosa, they’re actually tiny livebearers that somehow got named “killifish”), I’d recommend going for shrimp instead of crayfish as these have a lower bioload. It’s easy to overstock these tanks! Since you’re a beginner, I’d try Neocaridina shrimp. They come in all sorts of funky colors (red/yellow/green/blue/black/brown/orange), all of which have the same care requirements. You can have a look at the cherry shrimp caresheet if you’re interested. You can start out with a colony of 5-10, there isn’t really a set number for them as they produce so little waste. If you feel like they’re breeding too much, just sell or give away a few! Hope that helps 🙂

    • Reply Gaby February 10, 2018 at 10:59 pm

      Thank you sooo much but just one more question does having plants change the bio load

      • Reply Mari February 11, 2018 at 1:37 pm

        Not really. Maybe a tiny bit, since plant leaves die and decompose, but the effect of that should be pretty minimal because plants also make themselves useful by absorbing harmful substances 🙂

  • Reply Gaby January 31, 2018 at 12:21 am

    hi I have a 5 g fluvial tank and I’ve been very confused on how many times to change the water and such please help

    • Reply Mari January 31, 2018 at 11:04 am

      Hi! I can totally understand being confused. Here comes a wall of text:

      You do water changes based on your water values. Have you gotten a liquid aquarium test kit yet? It’s an absolutely crucial part of fishkeeping (don’t get the cheaper strips, they’re inaccurate). Try the API Master Test Kit. You also need it to cycle your aquarium (if you haven’t done that yet, go to that link first and forget everything else until it’s done).

      When you’re still figuring out how often to change the water, you just do water tests every other day or so and look at your nitrates. Those are a good indicator of how “dirty” your tank is. If they get above 15-ish, do a water change and see how the nitrates respond. Try to keep them at 10 or under. After a few weeks you should start seeing the pattern and you’ll know when to do a water change. Does that make sense? 🙂 it all depends on your stock, how often you feed, water temperature, plants, so there is no set schedule and you’ll have to figure it out yourself with the help of your test kit.

  • Reply Ty January 6, 2018 at 3:38 am

    I want to do an elaborate nana (5 gallon) aquascape, you didn’t really go into to much depth on the live plants, I am very beginner enthusiast when it comes to aquatic and semi-aquatic plants, however have enjoyed my massive jungle that ranges from air-plants to ground, a very small high humidity terrarium, I kinda began a couple of 10 gallon fish aquariums to establish better water for watering them, I use the water from the fish tanks (it’s chlorine free and pre low level fertilized, so much easier to “feed plants” this way. I have a 5 gallon aquarium with 5 small “feeder fish” I am not sure of species the sign on them said White Clouds but the store owner said that they are captive breed guppy/endlers I know that they were in really poor health when I got them but seem to be healthy and happy now, but they are going into the 10 gallon aquarium, the 10 gallon aquarium has 2 Neon Dwarf Grourmis and 3 dwarf frogs, the Neon Dwarfs are being moved to a 29 gallon aquarium, all tanks have hornwart and the 2 **5 gallon aquariums have Marino moss balls and I have ordered grass and baby tears, in both sizes (seeds).

    • Reply Mari January 7, 2018 at 8:30 pm

      Hi! Seems like you are definitely on a roll with the aquariums. If you want more info about plants I definitely have plenty – this article is strictly about fish hence the lack of plant info. The list of nano plants might come in handy for you.

      I do see a few things about the stock you mention that I’d like to address – the guppies/endlers or white clouds need an aquarium of at least 15-20 gallons, preferably more. They are active swimmers. Your dwarf frogs need a little more room as well. The absolute minimum for them is 15 gallons (as discussed in the dwarf frog caresheet) and they are best kept in a single-species setup so they aren’t bothered by their tankmates.

      Good luck with your aquariums and houseplants! 🙂

  • Reply Vishal November 17, 2017 at 7:41 am

    Hey aquariadise your articles are a real boon to beginners and experts alike 🙂
    I got a 3 gallon fish bowl with 4 Mollies in it(ik I need a larger aquarium but I don’t have the space for now ) what plants do you recommend? I’m just a beginner and I don’t really know much about aquarium plants
    Thank you 🙂

    • Reply Mari November 22, 2017 at 11:27 am


      I’d recommend plants from the 8 easy aquarium plants list, those are all suitable for beginners. But you do REALLY need a larger aquarium soon. 10 times as large actually – as you can read in the molly caresheet here the minimum tank size for them is 90cm which comes down to around 30 gallons. If you don’t think you’ll be able to provide that soon I really recommend you rehome the fish to someone who can, as they might not live a long life in such a tiny setup. Once you have rehomed them you can get some dwarf shrimp (your only option in a 3 gal).

      Good luck!

  • Reply Sim October 24, 2017 at 12:55 am

    I have a 5 gallon tank and one betta fish. If I added 2-3 least killifish, should I be okay from worry about bioload problems?

    • Reply Mari October 24, 2017 at 10:59 am

      I wouldn’t do that. In a tank that tiny I’d definitely stick to a maximum of 1 species. They’ll be so cramped I suspect the Betta might turn on his tankmates!

      • Reply Blanka November 9, 2017 at 3:35 am

        Hi, I was thinking of setting up a five gallon with maybe some shrimp, small fish etc.
        And I was wondering how many fish would you suggest having in a five gallon?

        • Reply Mari November 9, 2017 at 11:25 am

          Hello! All the information you need is in the article. There are only two fish species I would recommend for a 5 gallon: either a single male or female Betta splendens or 2-3x least killifish (Heterandria formosa). You can add some shrimp if you go for the Heterandrias, with Bettas it might not be a success.

          This might be less stock than you would have wanted for your tank but if you add more fish or other species you will run into problems. 5 gal is extremely tiny and just not suitable for most species. Good luck!

      • Reply SIM November 15, 2017 at 8:35 pm

        By chance, do you know the minimum number of least killifish one can have in a tank without the fishes being uncomfortable in the environment? the question probably doesn’t make sense . . .let’s see. . .
        For example, I have a 10 gallon tank with 10 chilli rasboras, and was given 3 male least killifish from a co-worker. Should I be worried that I don’t have enough least killifishes for them to be comfortable in the tank? The Least killifishes I have seem to socialize (in this case, shoal) with the chili rasboras, but I’m not sure if I should add more least killifishes to make them more comfortable.

        • Reply Mari November 22, 2017 at 11:36 am

          Hello! That’s a good question, but I think 3 is okay although I’m by no means an expert on them. I’ve read they can be kept in pairs or trios. If they seem to be shoaling with the rasboras and don’t seem skittish or stressed I’d leave it at this because you’re already pushing the stock with your current tank size.

          Good luck! 🙂

  • Reply Maddie October 21, 2017 at 10:15 pm

    Hi! I recently set up a planted 5 gallon, and it’s the process of cycling. I was hoping to add some RCS, but I’d love to introduce a tiny fish or two as well, especially since the shrimp need a more mature tank. I’m not sure if my local pet store stocks killifish — are there any other fish you could recommend? I currently have a betta in an 8.5, but I learned the hard way not to try to stock a betta and shrimp in the same tank. Are there any similar species that you would recommend? I have no problem with making it a shrimp-only breeding tank, but if there’s any way I can get a fish or two in there so that I can put something in a little earlier than the shrimp, that would be awesome.

    • Reply Mari October 22, 2017 at 12:41 pm

      Hi! That sounds like a nice little tank. I definitely agree RCS and Bettas are a recipe for disaster. As for least killifish, they aren’t actually real killies but tiny little livebearers. I doubt most pet stores stock them but you can always try looking for them online. They (along with a single Betta) are unfortunately the only fish option I’d recommend for a 5 gallon, and even those I’d personally keep in a larger setup. I know the internet is full of articles about fish that are “suitable for 5 gallon tanks” but I strongly recommend you stick with just the RCS and maybe 2x Heterandria formosa. A 5 gallon is TINY and things can just so easily end up going wrong if you’re not careful.

      As can be read in the article you do have a few fun invert options. The tiniest crayfish species (Cambarellus diminutus) would work in a 5 gal and they’re just as feisty as large crays; they leave shrimp alone. A few small snails can also work! Good luck 🙂

  • Reply About Me – Site Title September 4, 2017 at 3:01 am

    […] whilst living on campus were limited. So I did about the only thing I was allowed to do and go a fish tank and immediately fell in love with fish keeping. I’ve now been keeping aquariums for two […]

  • Reply Gaby August 11, 2017 at 9:01 am

    Also what size of tank that is resonable has a bigger variety of marine life that I can have (up to 15 or is 15 a bit too big)?

    • Reply Mari August 12, 2017 at 9:38 pm

      I’m not an expert on marine tanks at all but I do know they need to be even larger than freshwater, as many species get quite big. 15 gallons is considered a nano tank in this area as far as I know and your options are likely limited to just a few species. If you want a larger variety to choose from you’ll probably have to think closer to 150 gallons!

  • Reply Gaby August 11, 2017 at 8:58 am

    Hi i have 9 guppoes and a Bristol nose in my tanto and they have been perfectly fine since is this ok.

    • Reply Mari August 12, 2017 at 9:36 pm

      Hello. As you can read in the article that is unfortunately not okay at all, neither of those do well in a 5 gallon. They may seem perfectly fine but they aren’t. Please rehome them as soon as possible and then look into stocking your tank with one of the species on this list if you’d like.

  • Reply Nicholas Gatto August 3, 2017 at 6:34 am

    What can I keep with crystal black shrimp? Im considering buying 10-20 of them and also a dwarf crayfish in a 5 gallon tank or is that too filling for the tank?

    • Reply Mari August 3, 2017 at 11:00 am

      Hi! As long as you go for one of the tinier dwarf crayfish types that should be fine. So no Cambarellus patzcuarensis – Cambarellus diminutus is better. 🙂

  • Reply Jen July 30, 2017 at 11:53 am

    Hi…I’m just getting back into fish and I’m actually looking to stock a 7-gallon tank. I was thinking about a Betta, 2 pygmy corys (I know you say they do better in a larger tank… but I was hoping they’d do well in 7 gallons) and 2 snails. Do you think that would be too much?

    • Reply Mari July 30, 2017 at 12:11 pm


      I’d stick to just the betta and snails (Nerite snails would be great). You can also try dwarf shrimp if your betta isn’t the nippy type. The pygmy Corydoras are really not suitable for a 7 gallon, partly because they should be kept in groups. 2 is not going to cut it, you need to have at least 8 or so or they will be stressed and unhappy. With just the betta the tank will still be lively and fun, so no worries! 🙂

  • Reply Kat July 2, 2017 at 6:41 pm

    I’m setting up a 5 gal aquaponics system. So there will be more intense filtering of the nitrates than with a typical aquarium. My plan was to go with 7 neons and a few cherry shrimp. Will the addition of the aquaponics system as a cleaning element for the nitrates allow me to increase my stock levels, or not.

    • Reply Mari July 2, 2017 at 6:44 pm

      Hello! I guess it allows you to slightly increase your stock level but unfortunately neons are still not an option. They are just too big for such a tiny tank and need much more swimming room to be happy. I’d just stick to one of the species on this list! Good luck 🙂

  • Reply Abhishek Singh May 17, 2017 at 10:25 am

    I have 5 gallon aquarium and I have 1 shark and 3 gold fish and they lived happily for 3 months and then I bought another shark and the next day my 2 goldfish died. Can you explain why? Is there low oxygen level?

    • Reply Mari May 19, 2017 at 3:27 pm

      As you can read in the article, none of these fish are suitable for a 5 gallon aquarium. They all grow MUCH too large and are not compatible. Please rehome the remaining shark as soon as possible as it needs a way, way bigger aquarium. The goldfish likely died of stress and bad water values.

      Sorry I don’t have better news! Dwarf shrimp like cherry shrimp would be a better choice for this tank.

  • Reply Lauren Wilkes April 24, 2017 at 2:58 am

    I have a 5.5 gallon tank, could I put a female Betta in with my two nerite snails and two ghost shrimp?

    • Reply Mari April 24, 2017 at 10:21 am

      Hi! That should work. I’m not a huge fan of ghost shrimp with Bettas but it should probably work with a short-finned female.

      • Reply Lauren Wilkes April 24, 2017 at 6:47 pm

        Okay great! Thank you. Also do you have any other plant recommendations? I’m going to put some moss balls in there, but wanted to put a live plant or two. Something low maintenance preferably.

  • Reply Sieu Nguyen April 17, 2017 at 7:36 am

    I have a 5 gallon tank with a very senior Betta, I thought it needed life so I added some shrimp, which he ate. Then I tried 2 mystery snails. What a horrible idea! They made such a freaking mess! If you have a 5 gallon tank, just keep it simple. I decorated with live plants to make it more enjoyable for me. If my old man fish ever dies, I’d like some crabs and shrimp in there. This is about the only site I’ve found that gave proper advice. And I’m saying this from experience.

    • Reply Mari April 18, 2017 at 9:51 am

      Yeah, mystery snails grow so large they are really only suitable for tanks of 15 gallons and up! Glad the article was helpful 🙂

  • Reply Lucas April 2, 2017 at 10:08 pm

    Hey, I’m planning on putting about 10 red cherry shrimp and 2 amano shrimp in a 5 gallon rectangular planted tank. I’m not sure if the shrimp will do okay with the betta present…any advice?

    • Reply Mari April 3, 2017 at 9:13 am

      Hi! I can’t really tell you whether it will work because not all bettas are the same – some will hunt down and kill any shrimp right away, others leave them alone. In any case, make sure you have a plan B for the shrimp in case things go south!

  • Reply Clara March 22, 2017 at 2:47 am

    I have a 6.6 gallon tank and was planning on putting one male betta, 5-10 cherry shrimp, and 4-7 neon tetras in it. Plus live plants, and one artificial treasure chest with a whole in it. Would that work?

    • Reply Mari March 22, 2017 at 5:28 pm

      As you can read in the article that would unfortunately not work! Neon tetras are too large and active for a 6.6 gallon. 4-7 is also too little for a proper school and neons make bad betta tankmates due to their bright colors. With the Betta and the shrimp your tank is pretty much maxed out, so I’d definitely stick to just those two.

      Good luck 🙂

  • Reply Kyle January 5, 2017 at 8:21 am

    Hi! I happened to come across this article and wondered if I had a nice community aquarium. What do you think?
    I was thinking maybe 6 Glofish Danios, 5 ghost shrimp, some snails, and African Dwarf Frogs! (:

    • Reply Kyle January 5, 2017 at 8:22 am

      sorry didnt mention my tank size: 3.5 gallons

    • Reply Mari January 7, 2017 at 4:04 pm

      As discussed in the article, tanks under 5 gallons are unsuitable for any fish whatsoever and even 5 gallon setups can only sustain a handful of species. Of the species you mention, only the snails would work 100% – even for ghost shrimp, 3.5 gallons is on the small side. Please, no vertebrates – only inverts like dwarf shrimp and snails.

  • Reply Paul December 19, 2016 at 3:06 pm

    I have spent the last 3 days updating my knowledge about aquariums in general and then researching information about 5G tanks and was ready to throw in the towel until I found your site. Finally, a person with experience and sound advice. Thank you.

    I do have a couple of questions about the number of creatures I can have in this 5G nano. Suppose I selected one dwarf crayfish, 5 cherry shrimp, and a few snails, could I have one fish? Not a beta or a killifish. Although I have no experience with killifish, they just don’t look interesting. Any other suggestions?

    Also, can I mix different species of shrimp in the same tank.


    • Reply Mari December 19, 2016 at 3:50 pm

      So glad this article was helpful to you! To answer your questions:

      1. Aside from the species on this list, I cannot think of any fish that would work in a 5 gal, sorry! They all grow too large or need more swimming space. Single fish of many of the tiny species, such as microrasbora, would fit in a 5 gal but they need to be kept in schools and therefore require more space. I personally rule out fish completely when stocking a 5 gal and just stick to inverts. A crayfish, cherry shrimp and some snails would be great. The cray should provide all the personality you need!

      2. You can mix different species of shrimp in the same tank, but keep in mind that if you keep multiple color varieties of the same species together their young will revert back to a brownish wild color. A compatibility chart can be found here.

      I hope that helps, good luck!

      • Reply Paul Puente December 22, 2016 at 3:53 pm

        Thanks Mari. What if I went one size up to a 9 gal (34 l) tank. Could I keep a couple of fish with the inverts? If so, what do you recommend. Perhaps they could help with the shrimp “problem”, i.e., if my shrimp do have young I’m not sure what to do with them and perhaps the fish could provide that solution. That is, unless they decide that the adults are also rather tasty.


        • Reply Mari December 31, 2016 at 1:38 pm

          I wouldn’t worry about your shrimp multiplying, I’ve found that the population pretty much stabilizes after a while.

          As discussed in the article, there are a few fish you can keep in a 9 gal: a pair of least killifish would work, as would a betta (though the latter might be a little too effective when it comes to dealing with “shrimp problems”). For more stocking options you could also have a look at this article, though keep in mind that because a 9 gallon is still really small you should only go for the smallest, most inactive species. Hara jerdoni would be a cool option if you can find them.

  • Reply Diana December 18, 2016 at 2:56 am

    I have a 5 gallon tank with a very senior beta, I thought it needed life so I added some shrimp, which he ate. Then I tried 2 mystery snails. What a horrible idea! They made such a freaking mess! If you have a 5 gallon tank, just keep it simple. I decorated with live plants to make it more enjoyable for me. If my old man fish ever dies, I’d like some crabs and shrimp in there. This is about the only site I’ve found that gave proper advice. And I’m saying this from experience.

    • Reply Mari December 18, 2016 at 11:03 am

      Thanks for sharing, I totally agree! Less is definitely more in such a small setup. 🙂

  • Reply Nate August 2, 2016 at 5:56 am

    I just moved and my old tank was a 75 gal with 24 small fish in it (like the size of neon tetras and cherry barbs) it was a planted tank as well. since we moved I set up two 5 gal tanks (well 1 is a 5.5 but you get it lol) one of the tanks is your average 5.5 gal and the other is the Fluval Spec tank so its longer than it is wider, I have 9-10 fish in each tank because all my Local fish stores wouldn’t take my fish (missing a good offer for free lol) so I have them like I said 9-10 in each, with my other tank/tanks I was really good on keeping it clean and the plants and some of the fish helped me keep it clean to, so will these two 5 gallon tanks be ok with the very small 9-10 fish in them? and also im good about keeping required PH levels and average cleanliness of the tanks anyway but will the fish be ok, they seem to get along and be swimming calmly just acting normal. ???

    • Reply Mari August 2, 2016 at 12:02 pm

      Hi! Unfortunately neon tetra and cherry barb sized fish don’t classify as small fish – schooling fish are very active and need a lot more space than 5 gallons. If the aquarium store won’t take them, try rehoming them to other aquarists! The current situation is not ideal.

      Good luck!

  • Reply Lisa January 24, 2016 at 11:33 pm

    Hi Mari–

    Thanks for all the info! Your dwarf crayfish care sheet recommends an 8-gallon tank. Two in a 5-gallon tank seems much tighter. Does it just depend on planting & personality?

    • Reply Mari January 25, 2016 at 8:06 am

      Nope, it’s actually specified in the caresheet! The smallest crayfish species such as Cajun dwarf crayfish are suitable for 5 gallons and slightly larger ones like the CPO crayfish needs a little more, that’s why it’s set to 8. I’ve made a note in the article as well, though, as I’ve gotten multiple questions about it now. 🙂

  • Reply Gregg Martin January 24, 2016 at 3:46 pm

    I agree with most of this. Might I suggest that the dwarf livebearer/dwarf killifish with a tank of thick Najas g. work fine with a 5 gallon?


    • Reply Mari January 25, 2016 at 8:05 am

      I was kind of doubtful about adding these, but since I’ve listed the least killifish as suitable for 5 gallons elsewhere on Aquariadise I’ll add that one to the article 🙂

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