19 Coolest Freshwater Aquarium Fish for Small (10 Gallon) Tanks
By Eddie Waithaka @aquariawise
Fish keeping is interesting, but if you’re new to the hobby, it can be overwhelming given the choices you have to make. One of these picks is the fish to keep in a new fish tank.
Coincidentally, most beginning hobbyists, will start with small 10-gallon fish tanks. Which, although easy to set-up, get dirty quickly and make your aquarium water conditions quite toxic. For that reason, you will need to start with small hardy fish that are easy to care for, but also pops a cool-flair in your aquarium.
Therefore, this article will cover popular and unique fish you can use to embed a cool-factor to your small 10-gallon fish tank.
But first, here is a quick list of the coolest freshwater aquarium fish we are going to look at.
-Bettas -Guppies -Neon Tetras -Danios -Green Swordtails -Fancy Goldfish -Harlequin Rasboras -Cory Catfish -Southern Platyfish -Dwarf Gouramis -Kuhli Loach -Common Molly -Endlers -White Cloud Mountain Minnows
We’ll also look at 5 coolest freshwater inverts for small tanks.
-African Dwarf Frog -Mystery Snails -Ghost Shrimp -Amano Shrimp -Dwarf Mexican Crayfish
Bettas (Siamese fighting fish)
Bettas are brilliantly colored fish that often love to swim solo. They are Ok living in solitary therefore can live even in small ornamental vases and bowls.
Aquatic covers and dens decorations in tanks work great and go a long way in making your betta feel safe.
If you expect to have tankmates for your betta, you will need a bigger tank since the fish are territorial and need enough space to swim around.
Put bettas with small dull color fish that won’t spark aggressive tendencies in your fish.
However, Never put two male bettas in the same fish tank and avoid fin nippers as well.
They are native to the tropics, therefore, house them in warm aquariums with the water temperature between 78°F and 80°F, which means you will need a heater for your fish tank. Moreover, betta fish are quite sensitive to water ph and do best in neutral environments of about 6.5 to 7.
Luckily, these are labyrinth fish and will survive in low oxygen tanks aided by their capacity to get air from the water surface.
Guppies
Guppies are well known and popular freshwater aquarium fish for both beginners and seasoned aquarists. They are colorful, peaceful, relatively cheap, hardy, and easy to maintain.
Though there are nearly 300 different guppy species, most grow to about the same size and prefer tropical fish tanks.
Keep your guppy tank around 76°F and the ph from 5.5 to 8.5.
Fun enough, guppies are quite small and don’t take up a lot of space they’ll fit even in small 5-gallon tanks or modest size community tanks. The rule of thumb is one guppy per gallon of water.
Tank your fish with a handful of other guppies or place them in a community, even one with bigger species. However, make sure your guppies don’t turn into a quick snack for the big guys.
Neon Tetras
Neon tetras are small vibrantly colored freshwater fish that are easy to care for and quite popular amongst fish keepers. They have a peaceful temperament and are not fussy hence perfect for beginning hobbyists.
Adult size tetras grow to 1.5 inches and will comfortably live in a 10-gallon fish tank though it’ll depend on how many you plan on keeping. Remember neon tetras are shoaling fish so you’ll need to keep a group of at least six.
The aquarium should be tropical with a temperature anywhere between 68°F and 78°F. You’ll also need water that’s moderately hard with the ph of 6.5 to 7.
Neon tetras do well in community tanks as long as tankmates are not large or aggressive. Small peaceful fish such as rasboras, corys, and guppies are good companions.
Here, the rule of thumb is if the mouth of the tankmates opens large enough to swallow the neon, they will do it sooner or later should you put them together.
Danios
Zebra danios also called zebrafish are stripped fish that are prolific breeders and among the easiest types of egglayers to breed.
They are also active, easy to care for and can withstand an impressive range of water temperature and conditions.
Danios will generally do fine without a water heater in the tank though they are typically tropical species. This is because they are comfortable at a lower temperature even down to 60°F. However, the ideal range is 64°F to 75°F.
Zebra danios are surface dwelling fish and favor moving water, they also are peaceful fish that get along with most species though they will nip fins of slow-moving fish with flowy tails like angelfish and bettas.
They are best kept in a school but also love to be part of a community, in which case, put them with other shoaling fish that establish a pecking order.
Nonetheless, make sure these companions have a similar temperament to you danios.
A 10-gallon fish tank is the smallest tank you can comfortably add zebrafish, and make sure you go for smaller types in the family like celestial pearl danios.
Swordtail Fish
Green swordtails are almost as popular as guppies and bettas. This popularity stems from their ease of care, peaceful nature and their unique fins with a great variety of colors.
Female swordtails typically grow bigger up to 6.3 inches while males reach 5.5 inches maximum.
They love living in groups although they are not shoaling fish so you can add a couple or more in a modest size aquarium.However, the minimum tank size for one adult swordtail fish should be at least 15-gallons.
Swordtails are sturdy tropical fish that will tolerate a wide range of water temperatures but will live best in water that’s between 65°F and 70°F. That said, they are quite sensitive to temperature changes so you’ll want to keep your aquarium water considerably stable.
Green swordfish are generally peaceful despite males getting aggressive to other males of their kind. They also are social and enjoy good company.
To give your fish the best experience in your aquarium, put them in with other swordtails or their close cousins like platies, mollies and even angelfish.
Larger tetras are good companions too but keep them in schools of five.
Should you choose to keep more than one swordtail, a 10-gallon tank won’t cut it. You will need to use a bigger tank instead. Maybe a 40 or 50-gallon aquarium.
Fancy Goldfish
Goldfish make an excellent choice for both aquatic enthusiasts and new aquarium owners. However, they are one of the larger species and only a few fish from this family, like the fancy goldfish, will live in small fish tank.
Fancy goldfish is a group of unique varieties that add a glamorous look to your aquarium with each having its own selling point.
The minimum size of your aquarium will depend on how many fancy goldfish you keep with a single fish well suited for a small to a moderate size tank. However, two adults will require a bigger tank that is over 20-gallons.
Unfortunately, your choice of tankmates is limited when you keep these fish because goldfish generally live in cold water. So, you won’t be able to add other popular freshwater fish. Though one fancy goldfish will max out a small fish tank anyway.
When you finally upgrade to a bigger tank, put your goldfish with tankmates that are large enough not to be eaten, are not nippers and thrive in cold water.
Possible companions include zebra danios, rosy barbs, platies, bristle nose plecos and white cloud mountain minnows.
Harlequin Rasboras
Harlequins are small fish of the rasboras family and probably the most popular member in the freshwater aquarium fish keeping hobby.
Fully mature individual harlequin rasboras attain a standard length of two inches and will comfortably live in a 10-gallon fish tank. However, they are shoaling fish hence should be kept in a group of at least six individuals.
Add harlequin rasboras in your tropical fish tank with the water temperature between 72°F and 82°F, ph of 6.0 to 7.8 and a hardness range from zero to 15dgh.
Being peaceful fish, harlequin rasboras can be maintained in a community aquarium with other similarly sized and peaceful freshwater aquarium fish such as danios, cory catfish, small barbs, and other small rasboras.
Cory Catfish
Corydoras also called cory catfish is a genus of freshwater catfish that are priced for their many ornamental species. They are also well suited for tropical community aquariums as they get along with other species.
Virtually, all corys should be kept in schools because they get quite lonely and stressed when kept alone.
Most aquarium kept cory catfish will grow to about 2 to 2.5 inches and are well suited for tiny fish tanks. Some types you can keep in a small beginners 10-gallon include bandit, bronze, Julii, Panda, Skunk and three stipe corys.
They particularly enjoy tropical aquariums with water temperature anywhere between 72°F -80°F and ph 6.4 to 7.4.
Keep your corydoras in a school of 5 or more individuals. They are also generally social and will often play and swim in synch even with other species.
For that reason, cory catfish are compatible with pretty much anything that won’t try to eat them. Maintain them in a community tank together with mollies, fancy guppies, platies, swordtails, neon tetras, angelfish, danios and gouramis.
Southern Platyfish (Platies)
Southern platyfish, common platy, moonfish or just platies are a species of freshwater fish that are quite peaceful, easy-to-care-for and ideal for community aquariums.
They are also some of the best species for new fish keepers.
These vibrantly colored and highly variable fish grow to about 3 inches maximum hence are perfect for small 10-gallon fish tanks. Interestingly, they are brilliant breeders and life bearers like guppies, swordtails, and mollies are live-bearers.
All your platies in a tropical aquarium with the water temperature between 72°F and 80°F and ph 7.0 to 8.3 which is relatively alkaline.
Southern platyfish are compatible with most peaceful fish especially those they are closely related to like guppies, swordtails and mollies.
They will also live with tetras, gouramis, small barbs and inverts like shrimps and snails.
Dwarf Gouramis
Dwarf gouramis are peaceful and shy fish very closely related to betta fish. A pair will swim together and can live even in small 10-gallon tanks.
Some of the smaller species, such as the sparkling gourami which only reach 1.5 inches, can even be kept in Nano tanks as small as 5 gallons.
Like their betta cousins, they are labyrinth species which means they can breathe straight from the air. This helps dwarf gouramis thrive in tiny bowls with less oxygen.
Keep your pygmy gouramis in a tropical aquarium with the water temperature at 72°F to 82°F. They also like soft water (4 to 10dgh) with a fairly neutral ph of 6.0 to 7.5.
Courtesy to their peaceful nature, they are perfect for community tanks but keep them with other peaceful species that are not too large or aggressive.
Also, brightly colored fish are not good tankmates. They can sometimes cause male gouramis to become aggressive as they are perceived as rivals.
Some potentially good companions include dwarf cichlids, cardinal and neon tetras.
Kuhli Loach
If you are looking for a bottom-dwelling super cleaner, kuhli loaches are your best bet.They are small eel-like freshwater fish that belong to the loach family.
Kuhli loaches reach maturity at 2.7 inches and have a maximum length of 4 inches. Incredibly, they can live for up to 14 years.
You can house your kuhli loaches in a small 10-gallon fish tank with the water temperature between 75°F and 86°F. They love soft slightly acidic water with ph 5.5 to 6.5.
Because kuhli loaches are bottom dwellers, the size of your aquarium should be determined by the squares of its underside.
The fish feel better in a school of 5-6 fishes, so after you’ve gathered enough experience, consider getting a bigger tank that’ll fit more individuals.
Kuhli loaches are completely peaceful and are compatible with any fish of a similar size, from white cloud mountain minnows, bettas, harlequin rasboras, red-tailed black sharks to inverts like red cherry shrimp.
Mollies
Mollies are a small tropical fish known for their calm and peaceful nature which along with their brightly colored bodies make them a popular choice for freshwater aquariums.
Molly fish grow to between 2 and 4 inches and will live in small 10-gallon tanks. Put them in a tropical fish tank with the water temperature anywhere between 72°F and 78°F and ph 6.7 to 8.5.
However, mollies are rather diversified and will survive in freshwater, brackish and saline water plus a host of temperature.
They’ll also thrive in both common and separate tanks. In a species tank, place them in a group where females prevail.
In community tanks mollies get along well with peaceful and small fish like dwarf gouramis, bristle nose pleco, white cloud mountain minnows, harlequin rasboras, cherry barbs, guppies, and platies.
Endlers
Endler livebearers are small fish that are proficient breeders and often hybridize with guppies. They are colorful and easy to care for.
Endlers are also quite popular for their small size, peaceful temperament, and appealing colors.
Males grow to about an inch, and females can grow up to 1.4 inches. Consequently, they are some of the most perfect fish for small 10-gallon tanks. In fact, these livebearers will live even in smaller 5-gallon tanks.
Add your endlers in a tropical freshwater aquarium with water temperature anywhere between 72°F and 78°F, the warmer the fish tank, the faster your fish will grow.
They also prefer neutral to alkaline water conditions with the ph anywhere from 6.7 to 8.5.
When kept in a community tank, endlers will very likely get picked on because of their small size, so ensure your aquarium is densely planted to give them enough hiding places and a better chance at survival.
They are also infamous jumpers, so get a lid for your fish tank.
You should keep endlers with small peaceful fish that won’t devour them, good include white cloud mountain minnows, harlequin rasboras, neon and cardinal tetras.
White Cloud Mountain Minnows
White cloud minnows are small and colorful fish. They closely compare to neon tetras in color but not as expensive.
Adult size white clouds grow to about 1.5 inches and can live in anywhere from small 10-gallon tanks to big community tanks.
The fish are extremely forgiving with aquarium temperature and water quality hence good for new aquarists.
However, their ideal aquarium temperature is between 64°F and 72°F, but will survive in as low as 41°F. They are, therefore, ideal for keeping in unheated freshwater aquariums in cold climates.
Put your minnows in soft to moderately hard water anywhere between 5 and 19 dh and ph level should range between 6.0 and 8.0.
They are shoaling fish as well and thrive best in groups of at least 5 individuals. A single mountain minnow kept alone will get lonely and lose its vibrant color.
That being said, minnows are generally peaceful and happy with tankmates as long as they are not kept with larger fish that may eat them. For this reason, keep you white clouds with species like tetras, bettas, dwarf gouramis, and harlequin rasboras.
White cloud mountain minnows may look like tetras but are hardier and not as sensitive to water changes. They are, therefore, good starter fish for cycling new aquariums, though the process can be stressful.
This hardy nature and being more affordable have earned white cloud mountain minnows the moniker “Poor man’s neon tetras”.
Coolest Freshwater Aquarium Inverts For Small Tanks
Apart from conventional fish for your small fish tank, you can also add a few inverts some of which are extremely beautiful and others are excellent cleaners.
Here are 5 easy-to-care-for inverts you should consider adding to your small 10-gallon fish tank.
African Dwarf Frog
African dwarf frogs also called dwarf clawed frogs are aquatic inverts native to parts of equatorial Africa and quite popular in the pet trade industry.
They are desirable because of their low maintenance and are quite active rarely sitting for a long time. Although they at times float on one spot with limbs completely stretched out on the water surface.
The frogs are bottom scavengers and are a fantastic choice for controlling fry population in aquariums. They are also fully aquatic, so you don’t need to have a half-land fish tank.
The optimum temperature for African dwarf frogs is 75°F to 82°F, and the ph should be maintained between 6.5 and 7.5.
One or two African dwarf frogs will live happily in a 5-gallon aquarium. However, if they’ll share the tank with fish, you’ll need at least a 20-gallon tank.
Mystery Snails
These are peaceful slow-moving inverts that are quite popular additions to many tropical freshwater fish tanks.
Unlike other snails, they are easy to control and won’t feed on your live aquarium plants but will scavenge food remains from the gravel instead.
They also come in a variety of colors and will live with a host of tankmates.
Add mystery snails in at least a 5-gallon tanks or 10-gallons when kept with a few fish.
They do best in moderately hard water with a temperature range between 68°F and 74°F and a ph of 7.6 to 8.4. If you put your mystery snails in a low ph aquarium (acidic), the water risk degrading the snails’ shells.
Good mystery snails companions include fish like tetras, guppies and bettas and other inverts like Amano, cherry and ghost shrimps.
Learn more about mystery snails in this care guide that I wrote a while back.
Ghost Shrimp
Ghost shrimp also called glass shrimp are excellent additions to aquariums that are extremely hardy and can survive under a wider range of conditions than other freshwater shrimps.
Glass shrimps serve as feeders to larger fish or as sufficient tank cleaners, though they only live for about a year.
Add ghost shrimp in a small 5 to 10-gallon tropical fish tank with the temperature anywhere between 65°F and 82°F and a ph range of 7.0 to 8.0. They also enjoy a light flow of water which you can easily generate with a filter or air pump.
Ghost shrimp are peaceful and will live in community tanks. Unfortunately, they are mostly defenseless and risk being eaten by larger tankmates.
Therefore, they should only be added to a non-aggressive community of small fish that include tetras, cherry barbs, zebra, and kuhli loaches and cory catfish.
Amano Shrimp
This here is one of your solutions to aquarium algae problems. Amano shrimps are popular algae eaters that are also peaceful and broadly compatible.
They love heavily planted aquariums with the temperature anywhere from 70°F to 80°F and soft water (6.0 to 8.0 dH) and a ph range of 6.0 to 7.0.
A good rule of thumb is to add one Amano shrimp for every two gallons of water.
Sadly, Amano shrimp are seen as food by larger tankmates, therefore, maintain them with peaceful freshwater fish including tiger barbs, guppies, neon tetras, bristle nose plecos and inverts like cherry shrimp, mystery and nerite snails.
Apart from ghost and Amano shrimps you can also keep cherry and bamboo shrimps in your small aquariums.
Dwarf Mexican Crayfish
Dwarf crayfish are native to Mexico and the Southern United States. They are small peaceful species that are becoming quite popular inverts to keep in freshwater aquariums.
They remain relatively small with the largest species only growing to about 2 inches. Consequently, they can fit perfectly in small 10-gallon aquariums. However, if you want to keep more than two, you may want to consider a 20-gallon tank.
Dwarf Mexican crayfish prefer tropical fish tanks with the average temperature anywhere between 68°F and 77°F. The water should be moderately hard with a ph range between 7.5 and 8.0.
Moreover, the tank should include numerous hiding spots because crayfish molt regularly and require a place to hide while their shells harden.
Though not many crayfish species can live in community tanks because of their belligerence, dwarf crayfish should be fine. They generally prefer water ph value higher than 7 hence their tankmates got to love alkaline water too.
Some good companions include platies and mollies.
Small snails and shrimps may be harassed by dwarf crayfish, but apart from that, they’re mostly harmless to inverts.
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