Articles Stocking aquarium

Stocking a 5 gallon fish tank

January 24, 2016
stocking a 5 gallon fish tank

If you’re thinking about setting up a 5 gallon (18L) aquarium, it’s easy to get confused by the conflicting info spread on the internet and by aquarium stores. What are the best fish for a five gallon and which should you avoid? How many fish should you get? Five gallons is enough space to build a wonderful aquascape, but it’s very easy to overstock.

Keep reading for everything you need to know about stocking a five gallon aquarium!

A five gallon tank or cube is the smallest size aquarium that can actually hold fish, and your options are unfortunately a bit more limited than most sites suggest: you cannot keep schooling fish in a five gallon and invertebrates are actually usually the best option.

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: these 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 caresheet with more information about the particular species.

Fish to avoid

  • Fancy goldfish – need 20 gallons (75L) per fish
  • Common goldfish – exclusively pond fish
  • White cloud mountain minnow, celestial pearl danio – active schooling fish
  • Dwarf puffer fish – sensitive to water quality fluctuations and boredom
  • Neon tetra – active schooling fish
  • Guppy & Endler’s guppy – grow too large
  • Apple & mystery snail – grow too large and produce a lot of waste
  • Rasbora species – active schooling fish
  • (Pygmy) Corydoras – all species are too active and/or large, schooling

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! There are a few fun invertebrates that will do wonderfully in a tank of this size. My personal favorites are dwarf crayfish, which have a ton of personality but stay very small.

Suitable fish & inverts

  • 1 x Betta fish (full caresheet here)
  • 2x Least killifish (Heterandria formosa)
  • 2 x Dwarf crayfish (full caresheet here)*
  • 10 x Cherry shrimp* (full caresheet here)
  • 5 x Thai micro crab (Full caresheet here)
  • 5 x Nerite snail or assassin snail

*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 shufeldtii and not the larger CPO, which works better in at least 8 gallons (30L)

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 as 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, like the tiny Anubias nana. 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. All the aquariums in the video below are 5.2 gallons (20L) and although not everyone can replicate them at home, you can definitely achieve something similarly lovely and green.

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!

Cover image: Aquaristik – Unterwasserwelt mit Dekoration by konstmat

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  • 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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