Rainbowfish are beautiful and popular choices among aquarium owners. You can find them at several pet stores, but it’s important to choose compatible fish when you’re assembling an aquarium. Generally, rainbowfish are best with similar-sized or smaller freshwater fish that are not aggressive.
The best rainbowfish tank mates are other rainbowfish, tetras, guppies, mollies, swordtails, platies, select catfish, danios (zebras or pearls), rasboras, barbs, kribensis, angelfish, dwarf gouramis, loaches, plecos, peacock gudgeons, caridina shrimp, neocaridina shrimp, and snails.
Since rainbowfish are pretty calm and easygoing, it won’t be hard to find a suitable tank mate from this list.
If you are planning on having a tank of only rainbowfish, it is recommended that you have 6-8 together. Isolated rainbowfish are prone to loneliness and that can drastically affect their health. There are quite a few popular rainbowfish breeds:
- Axelrod’s Rainbowfish
- Banded Rainbowfish
- Boeseman’s Rainbowfish
- Crimson Spotted Rainbowfish
- Checkered Rainbowfish
- Desert Rainbowfish
- Dwarf Rainbowfish
- Lake Kutubu Rainbowfish
- Lake Wanam Rainbowfish
- Madagascar Rainbowfish
- Murry River Rainbowfish
- Neon Rainbowfish
- Red Rainbowfish
It is important to consider the gender of the fish as well. Male rainbowfish are more colorful than their female counterparts, but they are also more aggressive and will try to show off their picturesque scales among the other males.
Rainbowfish Water Conditions
“[Rainbowfish] do best between 74° F and 78° F, at a pH of 7.0 to 8.0 and alkalinity between 5° and 20° dKH (90 ppm to 360 ppm)”Source
Specific species of rainbowfish may have slightly different needs.
Any other tank mate that you introduce into the tank will also need to have compatible water condition needs.
Tetra fish are a common, colorful group of fish that come from Africa, Central America, and South America.
There are many tetra species, all of which are easy to keep in an aquarium. They are very social and are prone to illness due to isolation.
Tetras can live anywhere from 5-10 years. The larger the fish, the longer it will likely live. They can grow up to 1.5-2.0 inches long.
Guppies are a very easy fish species to take care of, making them one of the most popular pet fish. They are calm and social, which is one of the reasons they are such adaptable fish.
Guppies originate from South America but are now found all over the world.
Guppies can live up to 2 years. Male guppies can grow up to 1.4 inches, whereas females guppies can grow up to 2.4 inches.
Molly fish are quite easygoing. In the wild, they are found around North and South America. Because of cross-breeding, there are a few dozen different species now to choose from.
Mollies can live from 3-5 years and will grow up to 4-4.5 inches. However, certain varieties will grow up to 5 or 6 inches.
Occasionally, if you have male mollies and male rainbowfish that are similar in size, they may try to show off and begin fighting. The easiest way to avoid this is to have female rainbowfish for the male rainbowfish to be focused on or do not have a male molly with a male rainbowfish.
Swordtails are hardy fish that come from North and Central America. They like to be with other calm fish and can get shy when there are overly energetic fish in the same tank.
Swordtails can live up to 5 years old. Males can grow up to 5 inches and females can grow up to 6 inches.
Since the males can get aggressive, it is best to have them outnumbered by the females 4:1 in order to reduce the risk of males fighting.
Platy fish are very similar to swordtails but they don’t have a “sword” at the end of their tail. They are active fish, but they are peaceful with others.
Platies are native to Central America.
Platies typically live around 3 years, sometimes up to 5 years. They grow to 2-3 inches, but dwarf platies grow up to only 1 inch.
Most catfish come from South America, Asia, and Africa.
In captivity, corydoras can live 12-15 years and grow (on average) 2.5 inches. Otocinclus live 3-5 years and grow 1-2 inches. Suckermouth catfish can live up to 10-15 years and grow up to 12-15 inches in an aquarium.
Danios are really hardy fish. The two best species for rainbowfish are zebra danios and pearl danios.
Danios come from South and Southeast Asia.
Like the platies, they are very active school fish (need to be in a school of 4 or more fish). Because the zebra and pearl danios are so friendly, they are considered fish that can be kept with any tank mate. Zebra and pearl danios can live up to 3-5 years and grow up to 2 inches. Pearl danios may grow up to another half inch.
Rasboras are related to barbs, danios, goldfish, and koi. They are native to South and Southeast Asia.
They are considered best in small planted aquariums in groups of 7 or more. Although they are not too picky, rasboras are happier in well-decorated tanks.
Rasboras can live 5-8 years and grow up to 2 inches.
Fun fact: these fish can (and probably will if the opportunity presents itself) jump out of their tank. Make sure to keep a lid on!
“Barbs are semi-aggressive fish when housed in the aquarium individually, so it is important to maintain each species in groups of six or more. This technique will minimize aggression towards more passive tank mates.” Source
The most common type of barb fish to house with rainbowfish is the tiger barb. Tiger barbs can live up to 7 years and can grow up to 2.8-3.9 inches.
Kribensis fish are a dwarf type of cichlid. Although it is not recommended for rainbowfish to be with cichlids, the kribensis is safe to pair with rainbowfish due to its size and temperament.
They are native to Southern Nigeria and the coastal areas of Cameroon.
Kribensis fish can live up to 5 years in captivity and grow up to 3-4 inches. Depending on how active your rainbowfish are, there is a chance a kribensis would get stressed out since they are slower swimmers.
Angelfish are very graceful fish from South America. They prefer dimly lit areas with lots of foliage.
Angelfish can live up to 10 years in captivity and grow up to 6 inches.
“Water flow should be gentle, and décor should include large broadleaf plants and driftwood that is arranged vertically to simulate downed branches and trees. A few floating plants can also be added to provide shaded areas and cover.”Source
Gouramis are found in Eastern and Southern Asia. Because larger gouramis are prone to aggression, dwarf gouramis are better suited to be tank mates with rainbowfish.
Dwarf gouramis can live 4-6 years and grow up to 3.5 inches.
Male gouramis tend to be aggressive with each other so it is recommended to only have one male gouramis per tank. Females will tolerate each other.
The best species of loach to be with rainbowfish are clown loaches and botia loaches.
They are native to Central and Southern Asia.
Clown loaches can live up to 10 years in captivity and grow up to 4-5 inches. Botia loaches can typically live 5-8 years in captivity and can grow up to 6 inches. Clown loaches especially can be tank mates with almost any fish.
Plecos are algae eaters that will scavenge at the bottom of your tank. They are one of the best fish for beginners!
They are native to South America, but are popular in aquariums around the world.
In captivity, plecos can live 10-15 years and grow up to 15 inches. This is a fish that demands a lot of space.
Plecos will usually stick to the walls of your tank or swim along the bottom, leaving your rainbowfish to do as they please.
Peacock gudgeons enjoy being in a community tank but can get stressed out easily.
They are from Papau New Guinea, Australia, and New Zealand.
Peacock gudgeons can live 4-5 years in captivity and grow up to 2.5-3 inches.
Caridina and Neocaridina Shrimp
Caridina shrimp (also known as bee shrimp) and neocaridina shrimp come from Taiwan.
Neocaridina shrimp are similar to caridina shrimp, except they have different anatomy.
Similar to how plecos will scavenge the tank for algae, these shrimp will also look for algae or decayed vegetation.
They can live 12-18 months and grow up to 3-4 centimeters.
Little freshwater snails will frequently show up in your tank whether you buy them or not. They can come into your tank through live plants that you buy.
These little guys can reproduce faster than bunnies, but fortunately, they are helpful algae eaters. They will eat algae like plecos and decayed vegetation like caridina and neocaridina shrimp.