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Rainbow Sharks vs. Red Tail Sharks (The Key Differences)

Rainbow Sharks vs. Red Tail Sharks (The Key Differences)

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This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Many people think that rainbow sharks are among the neatest fish out there. You’ll also find that red tail sharks have many fans.

Some people mix these two fish up due to the fact that they have similar names. They are different fish, though.

What is the difference between a red tail shark and a rainbow shark? Are the two fish compatible?

Keep reading to learn everything you need to know about both fish. You’ll walk away with a greater understanding and appreciation of both fish.

These Two Fish Look Similar

The first thing to know is that these fish look quite similar. If you don’t know much about either fish, there’s a good chance that you’ll confuse the two.

Their bodies look similar and the coloration is close enough that you’ll think they’re the same at a glance. Of course, there are differences between the two fish that you can use to tell them apart.

Below, you’ll learn more about rainbow sharks and red tail sharks. Once you’ve read everything, it’ll be easier to distinguish which fish is which.

How to Tell Rainbow Sharks Apart From Red Tail Sharks

The easiest method for telling these two fish apart involves looking at their fins. There are differences in the fins that will make it easy to tell the fish apart even at a glance.

Rainbow sharks have red anal, pectoral, and dorsal fins. These fins will be black when looking at a red tail shark.

So you can use the differences in fin color to tell the fish apart. This is the most reliable way to tell the two fish apart because they look so similar otherwise.

Size Differences

You’ll also be able to note some minor size differences when looking at the two fish. Rainbow sharks grow to be six inches long.

Red tail sharks have the potential to grow to be six inches long as well. However, it’s more common for them to grow to be five inches long.

So a red tail shark will likely be slightly smaller than a rainbow shark when both are at full size. The size difference isn’t so large that it will be easy to notice, though.

Both Fish Are Bottom Feeders

It’s also important to note that both of these fish are bottom feeders. They’re both very active fish that like to hang out at the bottom of the tank.

The territorial nature of both fish will see them come into conflict with other fish. You need to give both fish plenty of space or they will wind up fighting with other fish a lot.

Minimum Tank Sizes

The minimum tank size for a rainbow shark is said to be 50 gallons. However, most experts say that these fish should be given 55-gallon aquariums.

A 55-gallon fish tank will be good enough for one rainbow shark. Generally, you’re only meant to keep one rainbow shark in a tank.

Rainbow sharks will fight with each other if you try to keep a group of them in the tank. It’s technically possible to keep these fish in groups, but you’d need a very large tank.

Since red tail sharks are virtually the same size, it’s also recommended to keep them in 55-gallon fish tanks. This is another reason why the fish are so similar.

Red tail sharks are also usually kept alone instead of in groups. They’re also so aggressive that they will fight each other unless given a lot of space.

Water Parameters

The water parameters for these two types of fish are similar, but they’re a bit different. Rainbow sharks do best when the pH balance of the water is kept between 6.5 and 7.5

The water temperature should stay between 72 degrees Fahrenheit and 79 degrees Fahrenheit when caring for rainbow sharks. Water hardness needs to stay between 5 and 11 dH.

Red tail sharks like the same water temperature as rainbow sharks. They can tolerate pH balance levels between 6.8 and 7.5.

The water hardness for red tail sharks can stay between 5 and 15 dH. So there are minor differences, but the water parameters for each fish will be quite close.

The Color of the Fish

The color of the fish will differ a bit. You’ve already learned that the fins are different when looking at both fish.

Rainbow sharks have red anal, pectoral, and dorsal fins. These fins will be black on the red tail sharks.

There are other color differences that need to be noted, but they’re subtle. Rainbow sharks generally have dark gray or blue bodies.

Red tail sharks have bodies with a deep black color. The difference between deep black and blue can be hard to spot unless you’re paying close attention.


It’s also worth mentioning that the lifespans of these two fish are a little bit different. Rainbow sharks have the potential to live for up to eight years.

However, it’s more common for the fish to live for four to six years in captivity. They can live for up to eight years with excellent care.

Red tail sharks can live up to six years. It’s very uncommon for red tail sharks to live much longer than six years.

So rainbow sharks will live longer than red tail sharks on average. Of course, you need to care for both fish well or else they might not even live two years.

Both Fish Are Affordable

Both fish are affordable if you’re looking to buy fish without spending a ton of cash. It’s common to find rainbow sharks and red tail sharks being sold at pet stores for less than $5.00.

They’re usually sold when they’re juveniles. You’ll buy the fish when they’re between one and two inches long.

At this age and size, it won’t cost much to get these fish. You can buy older and larger versions of the fish for a little bit more cash.

Caring for the Fish Is Similar

Caring for the fish is similar no matter which you choose to buy. You learned earlier that the water parameters are very close.

There are slight differences, but both of these fish have similar care requirements. They eat the same type of food and they require pretty much the same space.

Both fish won’t do well if you don’t keep the water in the tank clean. You need to make sure that you focus on tank maintenance and consistent water changes.

Do your best to keep the water clean and test it regularly using pH balance testing kits. Both of these fish are considered to be moderately difficult to care for, but rainbow sharks are slightly easier.

Both Fish Are Scaleless

It’s also important to note that both red tail sharks and rainbow sharks are scaleless fish. These fish have skin and don’t have scales of any kind.

Since they don’t have scales, they’re susceptible to certain things. Some treatments such as copper and salt will be dangerous for these fish.

So you need to be careful when these fish get sick. You only want to give them medicines that will be safe for them.

Also, both fish are vulnerable to elevated ammonia levels in the tank. This is why it’s so important to keep an eye on the water quality.

Can a Rainbow Shark Live With a Red Tail Shark?

Sadly, you’re not going to be able to keep rainbow sharks and red tail sharks in the same tank. Both of these types of fish are aggressive and they won’t get along.

When trying to keep both red tail sharks and rainbow sharks in the same tank, you’ll notice various aggression issues. The fish will be aggressive toward each other and will get into fights from time to time.

The fighting could be so bad that it’ll cause the fish to get injured. You never want to put your fish in harm’s way like this.

To avoid such issues, you should find compatible tank mates for red tail sharks and rainbow sharks. Keep them in separate tanks and you won’t have anything to worry about.

Both fish can be utilized as community fish, but they can’t live together. Keep this in mind and plan accordingly.

Final Thoughts

There are substantial differences between red tail sharks and rainbow sharks. Even if these two fish are very similar, they’re different enough that you need to pay attention.

You can tell the two fish apart by looking at their fins. They also have slightly different body colors.

Both fish have similar care requirements, but the water parameters are just a little different. You can’t keep these two fish together because they’re too aggressive and will fight in the tank.

Decide which fish you want. If you’re interested in both, be sure to keep them in separate tanks so both fish can be safe.

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