For those in a smaller living situation or trying to teach their kids how to responsibly care for pets, a 5-gallon tank is often the go-to for fishkeeping. But there’s a problem with that in a lot of cases: folks aren’t sure what fish actually do well in such a tiny aquarium.

Well, this list is here to help! From well-known fish like guppies and minnows to lesser-known species like the Asian Stone catfish or the red neon blue-eyes rainbow fish, these little guys will do well in small tanks, assuming you take proper care of them and maintain their fish tanks and make frequent water changes as needed.

Fish Species For Your 5-Gallon Fish Tanks and Nano Tanks

Typically, we advocate for larger tanks for fish. In nature, they live in ponds, lakes, streams, rivers, or the ocean – so limited fish to a tiny 5-gallon space isn’t the best of best choices for any species. However, for those who simply don’t have room for larger tanks and still wish to enjoy a freshwater aquarium at home, there are some species who do reasonably well in 5-gallon tanks. These fish species are small, interesting, and uniquely attractive, so no worries on that front!

White Cloud Mountain Minnow

White Cloud Mountain Minnows are an easy-to-keep species of fish for your freshwater fish tank. They come in a wide variety of types, like the longfin, golden, or “regular.” The golden ones are especially attractive and eye-catching, thanks to their blue eyes (a rarity in fish!), peach-yellow bodies, and red fins.

They’re also incredibly interesting aquarium fish to observe during breeding seasons. The males change colors and really show it out for the ladies.

They can eat almost any kind of fish food, don’t need a heater (i.e. cold water fish) and handle water parameters in a wide range. They’re great for nano tanks, small tanks, large tanks, or small outdoor ponds in the right climate.

Dwarf Pea Puffer

The Dwarf Pea Puffer, or simply dwarf puffer, is an inch long pufferfish that is yellow, has dark spots, and is known for having independently rotating eyes. This fish is known for being an aggressive carnivore that will eat any life snails or dwarf shrimp that it shares a tank with.

It is suggested to only have one in a five-gallon tank because they will become aggressive and start trying to bite any tank mates that they have. It’s important to give the fish plenty of live plants for it to explore and investigate so it will not become boring. 

Rosy Loach

Rosy Loach is known for having an outgoing personality. They are tiny scavengers that grow to be around 1.25 inches in length. This species of fish is known for being sexually dimorphic, so it is like you are getting two fish with a single school. The males are known for being a bright red-orange in color and the females are known for having a spotted pattern.

A school of six is enough to be able to see beautiful fish darting around the lower and middle levels of your aquarium.

Scarlet Badis

Scarlet Badis is a species similar to the Pea Puffer in that it is best to only keep one per five-gallon aquarium. However, there are several other fish that can safely co-exist with the Scarlet Badis. The male of this species is more popular and easier to purchase because of its distinct look of vertical red stripes accented with blue.

This species enjoys eating live food so it is important to not house it with snails or dwarf shrimp because this fish will not hesitate to try and eat either.

Mollies

Mollies are known for being classic freshwater aquarium stable. This species has been used in fishkeeping hobbies for a long time. Specifically, the Balloon Mollie is known for being lively and to have a very strong personality.

Similar to Guppies, this species is a livebearer that can produce babies and a very fast rate.

A five-gallon tank can easily hold a group of five male mollies with no problem.

This species does best in water that is between 76-80F.

Honey Gourami

Honey Gouramis have a similar look as the standard gourami. They are slim fish that have thread-like pectoral fins.

The Honey Gourami has an orange-red color which stands in stark contrast to the typical blue coloring of the standard gourami.

This fish species is small, reaching around two inches in length as adult fish. This smaller size makes them an ideal candidate for five-gallon tanks.

This fish is known for being peaceful and timid around fish that more active. For your fish to not get sick from anxiety it is important to pick the right tank mates.

This fish also needs to have clear access to the surface of the water because they are air-breathing labyrinth fish.

Betta Fish

Betta fish, known as betta splendens, are widely known for their beauty and strong personalities and attitude. It is well known that Betta fish hate and will try to kill other Betta fish, along with most other fish. This need to be kept isolate makes them perfect for living in five-gallon betta tanks.

Female Betta fish, especially the Koi Betta, are just as feisty and prone to violence as their male counterparts. The female has shorter fins which give them a more agile and streamlined look. Some say the fish looks like a colorful torpedo as it races along the inside of its tank. 

Betta fish are a fish species that has to have a stable temperature that is between 78-80F (25-27C).

Green Neon Tetra

Paracheirodon simulans, also known as the Green Neon Tetra, has the appearance of a normal neon tetra, however, it is an entirely separate species of fish.

It has a bright blue-green horizontal stripe that goes from its head to tail. This stripe causes it to stand out, even when it’s being viewed in a dark tank from across the room.

This species has a smaller length than the average neon tetra and stops at around once in length.

It is possible to comfortably house six of these in a five-gallon tank sized ecosystems. It is important to make sure you provide a lot of aquarium plants and areas for hiding places in when they feel stressed or afraid.

Guppies

Guppies are known for having a lot of energy and could easily swim circles around Betta Fish. They are known to show excitement and will swim against the glass when they notice that their humans are getting ready to feed them their next meal.

The male Guppie is known for coming in a wide range of colors, from a bright red to a pattern similar to that of a panda bear.

Because of their smaller size, it is possible to house four male guppies comfortably in a five-gallon tank size home. With just four Guppies in a  tank, there will be a flurry of colorful activity every time the fish are fed.

 Guppies need to be housed in an aquarium where the water temperature ranges between 74-80F and 23-27C.

Male and female guppies can be housed together, however, this species is known to reproduce rapidly and easily.

Celestial Pearl Danio

Celestial Pearl Danio is a species of fish that is highly sought after. This fish has a deep blue body with patches of cream color that dot over the body. This fish has fins that are bright red and have black striping.

Some people say that the fish’s colorful skin pattern mimics a star-filled night.

This fish’s unique looks make it an ideal centerpiece of a tank and people are willing to pay whatever price is needed to get it.

This is easy to care for fish but requires having stable water conditions. They are native to waters that are clean and full of rich vegetation.

Neon Tetras

Neon Tetras have been described as the result of a mad scientist combining minnows with jellyfish. However, the color and glowing of this fish species are natural. It helps these fish stand out in their native muddy Amazon basin waters.

This fish species is known for having a nervous temperament. It is important that the fish has plenty of places to explore and hide, along with other Neon Tetras.

If you are looking at using a five-gallon tank it is important to put no more than five Neon Tetras in a single tank.

Neon Tetras require to have high-quality water with a temperature kept between 74-80 Fahrenheit.

Licorice Gourami

The Licorice Gourami is a somewhat docile freshwater fish. The full adult length is around 1.5 inches long. Due to its shorter length, it makes an ideal candidate for living in a five-gallon aquarium.

As long as this fish is housed with the right tankmates it is known for being peaceful and shy. It is important to not place it with larger fishes that might bully or attack it.

Due to this fish’s temperament, it is best to only house a single male with only one or two females. If you have more than one male in such a small space there is a high likelihood they will be aggressive and possibly harm or kill one another. The males are notorious for fighting over territory and potential mates.

The male of this fish species is known to be smaller but more colorful than the female. The male has a white or blue edge on the fin that helps the fish stand out.

This fish species has a labyrinth breathing organ. This requires the fish to have easy access to the surface of the water so that it can take breaths of oxygen.

When putting together its tank, keep in mind this fish likes to have dim light and enjoys having lots of aquatic plants to explore and have as a place to hide.

Endler’s Livebearer

There was a point in time in which Endler’s Livebearer was grouped along with Guppies. At surface level, these two fish species do seem to be a lot alike. They both have small torpedo-shaped bodies along with an expansive fin. In addition, both fish species are livebearing.

Despite the similarities, Endler’s are a separate species. They can be found in a wide variety of colors that are often vibrant and eye-catching.

This species can naturally only be found in a single body of water, Laguna De Patos. Due to this, they have very specific water requirements to stay healthy.

Clown Killifish

The Clown Killifish is a species of fish that dwells in small streams in West Africa. This small fish does not grow quite reach the length of one and a half inches and prefers to live in shallow water.

Even though it is small, the Clown Killifish is a predator that excels at hunting and eating tiny microorganisms. This fish will ignore plants but hunts down insects.

This fish is also known for being very colorful, having stripes of black, yellow, and splashes of blue.

Chili Rasbora

Chili Rasboras are considered to be a species of fish called nano fish. A fully grown Chili will only reach 0.7 inches in length. This size makes this fish perfect for smaller aquariums.

Despite their small size, they are still capable of making a visual impact. They are known for having a very intense red color with black accents along the body and fins of the fish. The contrasting colors stand out and pop when they are swimming around a tank as a school of fish.

This fish species is native to blackwater ecosystems. While the tiny fish doesn’t need to have the water itself be dark, they do have very precise water quality requirements.

Harlequin Rasbora

The Harlequin Rasbora is a tropical, freshwater fish. These little guys are orange and have a distinct, striking black mark about halfway down their bodies. They’re a beautiful display fish that is active and energetic.

They’re small and compact, but I will note: they are schooling fish. For those keeping them in 5-gallon tanks, you’ll need to have a minimum of 4 of them and limit the stock in the tank otherwise. Otherwise, they simply won’t have enough room to happily survive. As it is, the space is really too small, but with frequent cleanings and top-notch maintenance, they can do well in the tiny environment. Make sure they have strong filtration and minimal décor is included in the tank.

Asian Stone Catfish

The Asian Stone Catfish is a unique, intriguing bottom dweller fish. They’re only 1.3 inches in length at full size. They’re known as Anchor Cats, as well, because they rather resemble an anchor if you look at them from above, thanks to their long pectoral fin spines. They use these to cling to pieces of driftwood and other objects.

Some folks think the little fish is lazy because they don’t move a lot, but that’s absolutely not true during feeding time! They roam around the bottom scavenging and scouring like little mad beasts.

They work well in 5-gallon tanks because they don’t require a lot of space and because they also help to clean up after other small fish in your 5-gallon tank.

Uniquely, they have the ability to change their colors to blend into the environment, so they are especially interesting in this way. Trying to find them can be like a treasure hunt! They’re peaceful but they need strict water parameters, so they’re not recommended for beginning aquarists.

Sparkling Gourami

Sparkling gouramiare happy little fish that reach about 1.5 inches in length. They’re great for beginner fishkeepers and don’t require a lot of space, so they do well in 5-gallon tanks, as long as the fish tanks are kept clean and water parameters are cared for reasonably well.

The little fish have a lot of color in their scales. Looking closely, you’ll spot polka dots on their fins, stripes or red and bright blue eyes.

These little fish are extremely active and love to zip around the tank – so be sure to keep them well-fed (but careful not to overfeed!) and provide them with some plants to dodge in and around as they play.

Dracula Minnow

This one has a fun name – the Dracula minnow. These tiny little fish max out at just 0.65 inches when mature and require a subtropical environment in their freshwater fish tanks. They are peaceful and chill, though rather active, and loosely school together. Ideally, in a 5-gallon tank, you’ll keep 10-12 Dracula minnows to ensure their happiness and mental health.

Pygmy Sunfish

The pygmy sunfish is only 1 inch long at full size. This helps to make them a perfect addition to a nano tank or other environment in a 5-gallon aquarium. They’re hardy and easy to care for, making them great for beginners, as well.

They do okay in poorly oxygenated environments, though, ideally you’ll aerate properly for their ultimate health. They also adapt easily to a variety of water conditions. They don’t require a heater, either, so they do well with other cold water fish that are peaceful and herbivorous.

They prefer heavily planted aquariums and need live foods like snails and micro-worms, insect larvae, et cetera. It should be noted that they’re carnivorous, so should not be kept with fish that are smaller than they – or they might just think the others are a snack!

These fish are super attractive with males coming blue electric. They should be kept in groups of three in your 5-gallon tank – one male and two females.

Least Rasbora

The Least Rasbora comfortably lives in a fish tank of 5-gallon size. They measure only 1 inch in length when fully grown. The adorable little fish is sometimes known as the Exclamation Point Rasbora because of the dark line that runs horizontally along it’s clear body, ending at the base of the tail where a dark spot resides.

The small tropical fish tends to a loner – not likely community tanks so much, apart from other Least Rasboras hanging out in a school. In fact, they do best in a school of 8-10 in the small 5-gallon tank, and they actually really thrive in this kind of setup. The small fish are shy, so the larger group in a smaller tank and larger community helps them relax. They tend to swim slowly, even in groups, and don’t need a lot of space for doing so.

They’re also pretty easy to care for, for they do great with beginner hobbyists at the helm.

Least Killifish

Least Killifish tend to be a little stand offish and shy. They don’t like loud or frequent noises, so they’re great for small aquariums in quiet spaces. They’re only an inch long when fully grown and thrive in rough conditions (besides the noise part). They don’t need a lot of water or air flow, coming from stagnant bodies of water naturally. They adapt well and aren’t picky about their diet – making them a great fish for beginners.

Red Neon Blue-Eyed Rainbowfish

This little fish measure about 1.5 inches at full size and do well in small aquariums with both floating and rooted live plants. They do best in mating group (sometimes referred to as a harem) of 3 females and 1 male. The fish tends to be peaceful and timid, so doesn’t do well with other tank mates typically, especially in a 5-gallon set up.

Fish to Avoid Keeping in 5-Gallon Tanks

Though there are common myths about goldfish doing well in tiny fishbowls. These fish and others commonly kept in small tanks should never be kept in tanks smaller than 10 or more gallons, depending on the species.

Goldfish, angelfish, cichlids of all kinds – none of these should be kept in small fish tanks. Most fish species, besides those mentioned and a few others, should be in tanks at least 20 gallons or larger.

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