one purple and yellow rainbow fish in a fish tank

Can you Keep Rainbow Fish Alone in a Fish Tank

5 min read

Rainbow fish are one of the most popular pets aquarists like to keep – they surely liven up any fish tank with their bright colors and tranquil behavior.

Besides the water parameters, you should also consider the social aspect of any fish you keep. Fish interact with each other in dynamic ways.

One question aquarists often ask is can rainbow fish live alone, or do they need to be in a group?

Find out the answer in this post and learn about rainbow fish care.

Let’s get started.

About the Rainbow Fish

Rainbow fish are freshwater fish native to Australia, Papua New Guinea, and Indonesia; they can be found in lakes, rivers, streams, and swamps.

2 rainbow fish swimming in the wild

Rainbow fish are a diverse family of fish, not a single species; in fact, the family Melanotaeniidae has close to 50 species. Many species are colorful, making them suitable for aquariums.

While the Boesemani Rainbow fish is the most popular, you have other species such as the Threadfin Rainbow fish, Axelrod’s Rainbow fish, Rainbow fish Rainbow fish, and Spotted Blue-Eyed Rainbow fish.

Males are more colorful than the females, and their colors get more prominent with age – keep this in mind when picking them young.

Rainbow Fish Requirements

Rainbow fish are relatively easy to care for as they tolerate a wide range of conditions. Here are their basic requirements:

·       Temperature of 72 – 82 °F (22-28 °C)

·       pH of 6.8 – 7.2

·       General hardness of 4-12 °dH

·       A lot of aquatic plants

·       Diet of bloodworms, flake, daphnia, brine shrimp, pellets, mosquito larvae, etc

Can Rainbow Fish Live Alone

The answer is no – rainbow fish are social animals meant to live in a group.

rainbow fish swimming in a fish tank

They are more than just shoalers – they are schoolers. Shoalers are fish that hang out together, but schoolers actually move together as one at the same speed.

They engage in this behavior because there is safety in numbers – your aquarium may be a safe place but it’s a fish eat fish world out in the wild.

If you keep a lonely rainbow fish, it could get stressed out. A stressed fish will often have a compromised immune system, which may lead to their demise.

On the other hand, a stressed rainbow fish will display its brightest colors; however, you should not keep them under stress for this sake – after all, what’s more important than keeping your aquatic buddies happy?

Moreover, males show off their colors when there are females around, so keeping them in a group can also liven up your aquarium. 

In any case, it is odd to have an aquarium with just one fish of any kind, so if you can go for more, we advise you to go for it.

You don’t go through the trouble of setting up an aquarium with various pieces of equipment to just have one fish in it.

One possible limitation could be the tank size, but if your tank is so small that you can only have one fish, then it’s probably not the best environment for that one fish either.

Remember, it’s much easier to maintain a tank the more water it has; having more water also dilutes the toxic effects of harmful chemicals such as ammonia, nitrite, and chlorine.

So consider upsizing your aquarium if you’re worried you have too small a tank to keep more than one rainbow fish.

How Many Rainbow Fish Should Be Kept Together

Now that we know it’s not a good idea to keep a rainbow fish alone, let’s look at how many you should keep – what’s the good number?

Boesemani Rainbow fish in a fish tank

Rainbow fish should be kept in shoals of 6 or more, preferably from the same species. If you have different species, get shoals for each of them.  

As for the gender of the rainbow fish, you should aim for a mix of males and females. You should get your ratio right, since males can be aggressive towards each other when it’s time to breed.

Getting 1-2 females for every male is recommended – the fighting can get really intense if there are too many males per female.

Having female rainbow fish around is good as it brings out the brightest colors from the males as they vie for mating rights.

The next question you may ask is what the right tank size is for a shoal of rainbow fish. It actually depends on the size of the species in question, since rainbow fish comes in various sizes and shapes.

For small species, you should opt for a 20-gallon tank, while larger species may require 50 gallons or more.

Rainbow Fish Compatibility With Other Fish

You figured out by now that rainbow fish should be kept in groups, but what about how they interact with other kinds of fish?

The good news is that rainbow fish are generally peaceful – they are an excellent choice for a community tank.

The Banded Rainbow fish in particular is a really peaceful creature, which makes it one of the best rainbow fish for community tank.

Rainbow fish can be kept together with a wide variety of other fish, including tetras, guppies, discus, loaches, danios, peaceful barbs, rasboras, catfish, non-aggressive cichlids, and medium-sized livebearers.

The rule of thumb is to get a similar-sized fish with a peaceful temperament; if one fish is too large, it will not hesitate to make a meal out of their smaller co-inhabitants.

Final Thoughts

Rainbow fish are social creatures, so you should not subject them to solitude by having just one fish. Doing so could make them stressed and unhealthy.

Moreover, your fish tank isn’t going to be that interesting to watch with just a solitary fish – one of the main appeals of aquariums is how the fish interact with each other.

A big part of rainbow fish care is making sure they have company; we have also explained how many rainbow fish should be kept together. 

Rainbow fish are a wonderful addition to your tank; as long as you get the right number and take care of them properly, you’ll have a vibrant and colorful tank.

Thanks for reading.

Written by:

Pet Aquariums

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