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!