Rainbow sharks are some of the most beautiful and attractive aquarium fish. However, despite their beauty, they are quite aggressive and territorial. This is the reason why many people keep them solo (just one shark per tank).

However, you do not really need to keep your rainbow shark solo. This is because there are several fish species and critters that you can keep together with your rainbow shark without risking any problems.

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In this article, I will share with you the fish species and critters that can live together with your rainbow shark for one reason or the other. But before I do that, here are some important things you need to know when considering tank mates for your rainbow fish:

You should never “mix” “shark” fish species in the same tank:

This is because all “shark” fish species are very aggressive and territorial. Therefore, having them together in the same tank is a recipe for disaster.

If you really want to house your rainbow shark with another “shark” species in the same tank, you should make sure it is massive (at least 100 gallons) and you should put plenty of tall plants and decorations in it so that they do not come across each other a lot.

You should never “mix” your rainbow shark with bottom-dwelling fish:

Rainbow sharks are primarily bottom-dwelling fish. So if you house your rainbow fish with other fish species that dwell at the bottom of the aquarium, you will be courting trouble. This is because it will consider the other fish as threats and will fight them.

However, you can house your rainbow shark with a handful of bottom-dwelling fish including plecos and loaches for reasons I will explain in the next section.

You should never house your shark fish with long-finned fish:

If you do this, your rainbow shark will bite the fins of the other fish. 

You should never house your rainbow shark with fin nippers:

This is because rainbow sharks have relatively long fins and will, therefore, be attacked by the fin nippers.

Now that you know what kind of fish you should not have as tank mates for your rainbow shark, it is time to know the fish species and critters that it can live together with. They include

Best Rainbow Shark Tank Mates

1. Rainbowfish

Your rainbow shark can live together with a rainbow fish. This is because of three reasons. First, your rainbow shark is a bottom-dweller. In other words, it mostly lives at the bottom of your fish tank. In contrast, a rainbow fish is a top-dweller.

This means that when you house your rainbow shark together with a rainbow fish, they will be in the same tank but not in the same territory. This will automatically eliminate/ minimize conflict. 

Second, your rainbow shark will grow to a maximum length of around 5 inches. The rainbow fish you introduce will also grow to a maximum length of about 5 inches.

So the two fish will have kind of the same size most of the time and this will make your shark think twice before attacking the rainbow fish for food.

Lastly, although your rainbow shark is aggressive, a rainbow fish is no pushover. It can and will fight back when it needs to. This will act as a deterrent and prevent your rainbow fish from attacking it. 

In summary, you can house your rainbow shark with a rainbow fish. 

2. Plecos

Your rainbow shark can live together with plecos. This is because of one key reason – plecos are big. Plecos typically grow to a length of about two feet long. In other words, plecos are often too big for rainbow sharks to regard them as food.

So while there are occasions when your rainbow shark will interact with plecos, it will just not be in its best interest to attack them and it won’t.

The best thing about having plecos as tank mates for your rainbow shark is that despite their bigger size, they will not threaten or pose any danger to your shark.

However, they will look for food in the same space as your rainbow shark. But this is not a problem as you can simply drop more food to satisfy every fish.

3. Zebra danios

Zebra danios can make the perfect tank mates for your rainbow shark. This is because of four reasons. First, zebra danios grow pretty big.

This means your rainbow shark will not consider a zebra danio or zebra danios as food because of their big size.

Second, zebra danios are schooling fish. In other words, a bunch of zebra danios will tend to swim together. For some reason, rainbow sharks are not often attracted by schooling fish. They are also not threatened by such fish.

Third, zebra danios are middle-dwellers. This means that your rainbow shark will not feel threatened by them in the bottom area of the tank. This will prevent confrontations. Lastly, zebra danios are very docile and they try very hard to avoid fighting. 

All these reasons show that zebra danios are some of the perfect tank mates for a rainbow shark.

4. Loaches

Loaches are bottom-dwellers. As mentioned earlier, rainbow sharks are also bottom dwellers and they usually tend to be pretty aggressive with other bottom-dwellers.

However, loaches usually tend to live in the same territory as rainbow sharks in the wild. So rainbow sharks are pretty used to them and they do not feel threatened by them. For this reason, if you introduce loaches to your fish tank, your rainbow shark is unlikely to attack them because it won’t feel very threatened.

Moreover, loaches are too big to be eaten whole by your “shark.” 

However, there is a need to not that there are many rainbow shark species. While some may be okay with loaches, others may attack them.

Nevertheless, most rainbow shark species have no problem whatsoever with living in the same space as loaches. This is the reason why loaches are great tank mates for rainbow sharks.

5. Barbs

Barbs are generally top-dwellers. This means that housing them in the same tank as your rainbow shark is no problem because they will be in a different territory (rainbow sharks are bottom-dwellers).

The fact that the two fish species will not be in the same territory means that your shark won’t feel threatened at any given time and, therefore, will have no motivation to attack its new tank mates.

Moreover, barbs are also a schooling fish. And as explained above, rainbow sharks do not really feel threatened by schooling fish so they tend not to attack such fish.

Also, barbs are relatively big. So they cannot really fit in the small mouths of rainbow sharks. This means they cannot be eaten or seriously harmed by rainbow sharks.

The best species of barbs that you can use as tank mates for your rainbow shark include the zebra, tiger, gold, and rosy barbs.

6. Rasboras

You can house your rainbow shark with rasboras without causing any problems. The main reason why is because most rasboras are schooling fish. And as mentioned above, rainbow sharks do not feel threatened by schooling fish and, therefore, do not attack them.

Furthermore, while rainbow sharks are bottom dwellers and feeders, rasboras are middle-dwellers and feeders. Therefore, the two species of fish will not interact frequently if you house them together and this will reduce the likelihood of confrontations.

Moreover, rasboras are generally big enough not to fit in the mouths of rainbow sharks. Therefore, rainbow sharks cannot eat them. However, there are some species of rasboras that are small enough to be eaten by rainbow sharks. You should avoid mixing such species with your rainbow shark in the same tank.

7. Gouramis

Gouramis are very peaceful. They do not disturb or attack other fish. And they are also too big to be attacked by rainbow sharks. However, there are some species of fish that are small and can be attacked or eaten by a rainbow shark.

Therefore, when buying gouramis for your rainbow shark tank, you should make sure they are the species that grow to a big size that cannot be eaten or attacked. Species such as moonlight, pearl, and blue gouramis. 

One more thing to note about gouramis is that they are not really bottom-dwellers so your rainbow shark will not view them as threats. And, therefore, it will have no reason to attack them.

The above statements show clearly that gouramis are good tank mates for rainbow sharks.

8. Snails

nerite snail

You can house your rainbow shark with nerite snails and other aquarium snails because it won’t care about them and the snails won’t care about it. So rainbow sharks and nerite snails are great tank mates because they largely ignore each other.

Moreover, even if your rainbow shark goes berserk and tries to attack a snail tank mate, it will not manage to cause any harm because of the hard protective shell on it.

So snails are absolutely brilliant tank mates for rainbow sharks.

9. Ghost shrimps

Ghost Shrimp

Ghost shrimps are great to watch. Adding them to a fish tank adds character and beauty. They are great tank mates for a rainbow shark because they are “ghosts.” What I mean by this is that they can become transparent and, therefore, effectively camouflage. Thus, if you put them in the same tank as a rainbow shark, the shark will not be able to easily spot them and fight them and/ or eat them. Moreover, you can make it even harder for your rainbow shark to spot your ghost shrimps by adding tall live plants and decorations to your tank. This is because the plants and the decorations will create perfect hiding spaces for your shrimps.

Furthermore, it is important to note that rainbow sharks usually only eat what they are familiar with. Since a ghost shrimp does not look anything like a fish, it is unlikely that your rainbow shark will try to attack one if it spots it.

10. Rummies

Rummies are very exciting looking fish. And according to many experienced aquarists, you can keep them together with young rainbow sharks. And if you house them from very early on, it is unlikely that your young rainbow shark will try to attack them later on as it matures. 

However, to prepare for the worst-case scenario (your shark attacking your rummies), you should grow tall aquarium plants in your tank and add caves and decorations. This will create hiding spots where your rummies can run into in case your shark goes crazy one day. But it will be very unlikely.

As you can see from the above information, there are several fish species and critters that you can add to your fish tank as tank mates for your rainbow shark. Rainbow sharks are aggressive, yes but they can live with the fish and critters I have included in the list above for one reason or the other. Size difference is one of the reasons why your rainbow shark won’t attack some of the fish I have included in the list above. The fish grow too big for them to fight or eat. 

You can add one or two of the best tank mates for rainbow sharks in the list above depending on the size of your tank. Don’t let your “shark” be lonely. Give it “friends” it can’t eat.

What you need to know about rainbow sharks

Rainbow sharks are aggressive. However, they are not as aggressive as real sharks. Below are some facts you may or may not know about rainbow sharks.

  1. Appearance: Rainbow sharks often have a dark blue or black elongated body. They can be bright blue sometimes. They have pointy snouts and fins in a different color. This is the reason why they are called “sharks.”
  2. Maximum size and lifespan: A rainbow shark can grow and become as long as six inches in length. And it can live for as long as six years if well taken care of.
  3. Living with other rainbow sharks: In the wild, rainbow sharks have no problem living together in a community. However, in tanks, they fight each other. This is because they are very territorial.
  4. Close relations: Rainbowfish are surprisingly closely related to the very docile goldfish than to any other fish species. They are not even one bit related to sharks. They are just called rainbow sharks because of their appearance. 

However, while they are closely related to goldfish, they cannot be kept together with the species in a tank. They will eat the goldfish. Not nice but it is the reality.

  1. Behavior: When in captivity, a rainbow fish will typically stay at the bottom of the tank in which they are kept. It will also feed in the same territory. In terms of food, rainbow fish will scavenge for food at the bottom of the tank. It will also seek and eat algae in a fish tank. If you can, you should include plants, caves, rocks, and other decorations in your tank. Such things will create perfect hiding and resting spots for your shark and it will like them very much.
  2. Space needed: You should not keep a single rainbow shark in any tank with a capacity of fewer than 30 gallons. Such a tank will be too small for it. Moreover, it is when you keep or cultivate a rainbow shark in a small tank that they become very aggressive and dangerous to their tank mates.
  3. Water parameters: The ideal water temperature range for a rainbow shark is between 75 and 81°F. The ideal water hardness level is from 5 to 11°Dh. While the ideal pH level is between 6 and 8.

Frequently Asked Questions about rainbow sharks

Do rainbow sharks really kill other species of fish?

Yes, they do. However, as mentioned earlier in this article, rainbow sharks are compatible with some fish so they will typically not kill the fish they are compatible with. However, when with non-compatible fish in a smallish fish tank, they may feel as if their territory is being encroached and they may react with aggressiveness.

What is wrong with housing my rainbow shark with a betta?

In terms of water parameters? Nothing. However, both fish are aggressive and very territorial. Housing them together in a tank will likely result in multiple confrontations.

Conclusion

A rainbow shark is a nice fish to have in your tank. However, you cannot just throw in fish and critters into your tank to be its tank mates. This is because it is very aggressive and territorial. Nevertheless, there are fish it can live with without harming or fighting. They include plecos, zebra danios, ghost shrimps, and rainbow fish.