6 Best Fish for a 5 Gallon Tank

Posted by on 4/17/2024

If you're considering a 5-gallon tank, then you'll be a bit limited in terms of stocking options. Aquarists new to the hobby may mistakenly think that a 5-gallon tank is easier to care for due to its small size - but in fact, the opposite is true! The small amount of water volume means the tank is more susceptible to rapid swings in water chemistry changes, which can be disastrous for your tank's inhabitants.

While our preference is for shrimp in a 5-gallon tank, hobbyists set on fish have a few options to choose from. 

Our Favorites

Due to ammonia buildup from fish waste, you'll want to make sure your 5-gallon aquarium isn't overstocked. It's why shrimp are such good candidates for tanks of this size, as they coincide with a low bioload (less decaying food, waste, etc.) Unsurprisingly, for those who are interested in fish, small fish are a requirement for a 5-gallon. Let's get into some of our favorites.

Betta Fish

Arguably the most recommended fish for a 5-gallon tank is the Betta Fish. Due to false advertising from some of the larger pet chain stores, the care requirements for betta fish tend to be a bit misunderstood. A 5-gallon aquarium with a heater and a few live aquatic plants is the baseline recommendation for caring for this fish, and hobbyists who provide these amenities will be rewarded with an active fish that displays a lot of personality and vibrant color.

Betta Fish
Ron Kuenitz/Shutterstock.com
A Galaxy Koi Betta

Ember Tetras

Hobbyists who have never seen Ember Tetras in person may be surprised to see these fish on the list, but Embers tend to be quite smaller compared to the more popular Cardinal and Neon Tetras that are often available at Local Fish Stores. Adults tend to top out at about 0.8 inches in size, making a small group of about 6 of them in a 5-gallon tank a viable option. Similar to the Green Neon Tetra, Ember Tetras will "color up" once your aquarium lights kick on - truly a sight to behold!

Ember Tetra
An Ember Tetra

Celestial Pearl Danios

Similar in size to the previously mentioned Ember Tetra, is the vibrant Celestial Pearl Danio. These fish are a relatively recent addition to the aquarium hobby, only gaining popularity around the year 2006 when its native country of Myanmar allowed for their export. It's no surprise as to why these fish are so popular, their iridescent speckles and peaceful temperament make them one of the most sought-after nano-sized fish in the hobby. Just like Embers, hobbyists should have no issue keeping a small group of 5-6 of these fish in their 5-gallon tanks.

A Celestial Pearl Danio
Celestial Pearl Danios, native to Myanmar

Dwarf Pea Puffer

Next up on our list is the adorable Dwarf Pea Puffer. Native to Karnataka, a state in the southwestern region of India, the Dwarf Pea Puffer is known for its unique appearance and curious personality. Similar to other puffer species, dwarfs are known for their intelligence, often observing movements both in and outside of the tank. Similar to the Betta, only a single Dwarf Puffer should be kept in an aquarium that's 5 gallons in size.

Dwarf Pufferfish
Toxotes Hun-Gabor Horvath/Shutterstock.com
A Dwarf Pea Pufferfish

Rocket Clown Killifish

Another gorgeous fish is the Rocket Clown Killifish. Hobbyists unfamiliar with Killifish may notice their upturned mouths, which they use to hunt down food sources along the water's surface. Due to their preference for surface-dwelling food, killifish are known to stay near the upper portion of the tank. In the wild, they'll often jump out of the water to catch mosquito larvae, so hobbyists will need a tight-fitting lid to prevent these fish from jumping out of their tanks.

A Rocket Clown Killifish
A Rocket Clown Killifish, named after it's rocket-like tail fin

Medaka Ricefish

Native to Japan, Japanese Ricefish are popular small-sized fish that can live in both warm and cold-water environments. With an appearance that resembles a small grain of rice, these active fish make an excellent addition to a nano-sized tank. However, hobbyists should be aware that these fish breed frequently, so we recommend having a larger-sized tank at the ready in case things get out of hand. These fish can be found in both platinum blue and white color morphs, and hobbyists should have no issues keeping a small group of 5-6 of them in their 5-gallon tanks.

Japanese Ricefish
Pavaphon Supanantananont/Shutterstock.com
A white-colored Japanese Ricefish


As you can see, hobbyists are somewhat limited when it comes to fish in such a small tank. Luckily, there are a few options for those willing to take on the challenge. But if fish aren't your thing, don't sleep on shrimp! Neocaridina and Caridina shrimp come in a variety of colors, and hobbyists can keep much more shrimp than fish in a 5-gallon tank. 

Now that we covered a few stocking options for a 5-gallon tank, do you think you'll pursue some of the fish on this list, or will you scrap the idea altogether in favor of a shrimp tank? Let us know in the comments, and be sure to visit our marketplace, where you can buy and sell with other aquarium hobbyists.

Image of Miles Harrison

Miles Harrison

With over a decade of aquarium experience, Miles can be found writing about saltwater and freshwater aquariums. When he’s not writing about fish, you can find him going for a run or building websites, such as this one!