Red Tail Shark 101: Care, Size, Tank Mates, Food, & More

Red Tail Sharks are an eye-catching freshwater fish that we’ve been drawn to for quite a while. Their simple yet striking appearance is something you don’t often see in other species.

Because of their aesthetic appeal, this fish has gotten a lot of interest from the aquarium community over the years. This is in spite of the fact that the fate of the species is actually in a bit of trouble.

But these fish are more than just pretty. They’re actually fairly easy to care for and can be low-maintenance if you place them in the right habitat (more on that later).

This guide will teach you everything you need to know about Red Tail Shark care. You’ll learn good options for tank mates, what food they eat, how big they get, and much more!

Let’s get started.

Species Summary

The Red Tail Shark (Epalzeorhynchos bicolor) is a freshwater fish that is found in Thailand. It is often referred to by other names like the Red-Tailed Shark, Red-Tailed Black Shark, Fire Tail Shark, and Red Rail Shark Minnow.

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The origin of these names are rather obvious when you see one. The majority of their body is black except for their caudal fin, which is red.

There was a highly condensed population of Red Tail Sharks in Bueng Boraphet, which is the largest freshwater lake and swamp area in the middle portion of Thailand. There are a number of streams that trickle out from this body of water where you could find this species as well.

The reason we say “could find” is because this species is now considered to be Critically Endangered. As a matter of fact, the Red Tail Shark was assumed to be extinct as recently as 2011. Even though it has been verified that this fish is still around in the wild, their numbers are a fraction of what they once were.

This is something that a lot of people in the aquarium scene don’t realize. You see these freshwater aquarium sharks quite a bit in tanks all over the world and are talked about in forums often as well. Because of this, it can seem like everything is fine and dandy (when it definitely isn’t).

Author Note: Although there hasn’t been any hard data that shows the aquarium industry is to blame for the drop in population, we like to treat this species with an extra amount of respect. This means we only recommend getting one if you’re absolutely sure you’re going to be committed enough to take care of it.

While that should always be your approach no matter what fish you keep, we recommend taking the time to be 110% sure before getting a species that’s endangered.


The average Red Tail Shark lifespan is between 5 and 8 years. While there’s always an element of randomness to this, there are some things you can do to ensure that they live as long as possible.

Among them are buying your fish from a reputable seller, keeping them in a great habitat, and reducing stress by keeping them with the proper tank mates. Don’t worry, we cover all of those topics in this guide.


The appearance of the Red Tail Shark is pretty straightforward. From a color standpoint, there are only two colors to mention (black and red), and their bodies have a classic shark-like appearance.

One of the reasons why this fish is so striking is the sudden change in color from black to red. The majority of their body is completely black with no deviation or patterning anywhere (even on the fins).

But that all changes when you get to the caudal fin.

Right at the end of the caudal peduncle, the color shifts from black to bright red. It doesn’t shift gradually either. There’s literally a vertical line where it does a complete color change!

Side view of a Red Tail Shark

On their caudal tail, this red color is steady throughout. Some specimens might have a bit more of a translucent red near the edge of the fin, but that’s not the case every time.

Their bodies look very much like a shark (even though they technically aren’t). The Red Tail Black Shark has a long and thin body that’s shaped very much like a torpedo.

Their dorsal fin begins roughly halfway back on their body and resembles the classic trait of the scary fish we’ve come to fear in movies. The rest of their fins (excluding the caudal) are much smaller.

Author Note: These fish are often confused with Rainbow Sharks. It’s very important to make this distinction because these two fish are not viable tank mates and will fight if you keep them together.

Red Tail Shark Size

The average Red Tail Shark size is between 4 and 6 inches when fully grown. This assumes good care and genetic conditions.

In our experience, this species will typically end up being on the higher end of that range as long as you’re giving them proper care. We don’t know many aquarists who have a Red Tail under 5 inches.


Red Tail Shark care is often misunderstood by many aquarists. They hear how these fish can be aggressive in certain situations (which are easily avoided) and assume that they’re difficult to care for.

But that’s not the case.

These fish are pretty straightforward and easy to care for as long as you know the basics. They’re pretty hardy and can handle a reasonable range of water parameters which makes things a lot easier as an owner.

With that being said, if you set them up with an insufficient tank you’ll definitely have some problems. Read this section to learn everything you need in order to start things off right.

Tank Size

The recommended tank size for Red Tail Sharks is 55 gallons. Even though these fish aren’t massive, they’re quite active and need a good amount of room to swim.

This space also comes in handy for reducing the possibility of aggressive behavior. They can get territorial, and that only gets worse when they’re right on top of one another.

Author Note: While a lot of aquarists have done fine keeping two of these in the same tank (more on that later), it’s highly recommended that you increase the tank size significantly if you’re going to attempt this.

Water Parameters

Water parameters are an element of Red Tail Shark care that you won’t have to worry much about. These fish are fairly hardy and can tolerate a reasonable range in the following levels:

  • Water temperature: 72°F to 79°F (we prefer the upper half of that range)
  • pH levels: 6.5 to 7.5
  • Water hardness: 10-15 KH

Even though these aren’t the most sensitive species in the world, you should always check the water parameters on a consistent basis. This will prevent anything from shifting out of the recommended windows and impacting the health of your fish.

Invest in a solid aquarium testing kit to make sure the readings you’re getting are accurate. We’ve known aquarists who’ve done serious damage to their tank as a result of a false reading!

What To Put In Their Tank

Setting up a good Red Tail Shark habitat is pretty simple once you understand their native environment. As we mentioned earlier, this fish comes from the largest lake and swamp area in central Thailand. These waters are full of vegetation, wood, and rocks.

This means you should include these items if you want your fish to be comfortable. Not only will they provide enrichment and something these fish are familiar with, but it will also reduce their aggressive tendencies.

Any durable and reasonably-sized plants like hornwort or water wisteria will work well. There are many owners who’ve said their Red Tail Shark decided to make it’s home in plants instead of caves.

Epalzeorhynchos bicolor swimming in a planted tank

Some driftwood is a good inclusion that will provide some variety and places for fish to hide. Make sure there’s enough room to swim after adding everything. It’s easy to go overboard when decorating a tank!

Author Note: The ideal substrate for Red Tail Sharks is moderately-sized gravel or pebbles. Red Tail Sharks are bottom-dwellers for the most part, so getting the substrate right is very important.

Disease Potential

Red Tail Black Sharks don’t have a particular disease that afflicts their species, but they can get any of the common freshwater diseases that exist.

The most common are Ich and fin rot. The likelihood of this happening goes down significantly if you provide them with great care and high-quality water conditions, but the possibility is always there.

Our recommendation is to focus on prevention rather than being paranoid about treatment. If your fish are unlucky enough to get sick, there are a bunch of great resources online about how to deal with the disease (we’ll be adding some to our site very soon as well).

Until then, do your best to feed your Red Tail Shark great food and provide them with a top-notch habitat. Be consistent about monitoring parameters and doing partial water changes (this is the most common cause of illness).

Author Note: You should also spend a few minutes each day inspecting your fish. Take a close look to see if you notice anything out of the ordinary on their body (or in their behavior). The sooner you realize that something is wrong, the better.

Food & Diet Recommendations

You have a lot of options when it comes to Red Tail Shark food. These fish are omnivores and are not picky about what they eat!

In their natural habitat, they eat plants, insects, and various crustaceans. Obviously it’s hard to replicate their normal diet in captivity, but it’s not that hard to come close!

Most owners feed this species flakes or pellets as the primary source of nutrition. Nothing fancy here, just go with your favorite high-quality provider.

You can also throw in some other foods for the sake of variety and enrichment. We’re firm believers that doing this will not only keep your Red Tail Shark happier, but it will extend their lifespan as well.

Brine shrimp, bloodworms, and tubifex are some of our favorites. These are not only rich in protein and nutrients, but they bring out some different active behaviors in your fish.

Some aquarists recommend including some vegetables like zucchini or cucumber for the sake of variety as well. Make sure you cut the pieces small enough so they can be easily eaten!

Because Red Tail Sharks aren’t picky eaters, it’s important to make sure you’re not overfeeding them. If they can’t eat what you gave them in a couple of minutes you’re probably giving them too much food.

Also, keep an eye on how much food is actually being eaten and how much is falling to the substrate. Uneaten food can quickly compromise the quality of the water which increases the risk of illness.

Behavior & Temperament

Red Tail Sharks are a very active fish that are a lot of fun to watch. You’ll often see them swimming near the bottom of the tank while darting away to investigate other areas they find interesting.

This activity level is why it’s so important to give them an adequate tank size and set their habitat up properly. They need room to roam!

Any aggressive tendencies they display will be exaggerated by insufficient space or the wrong tank mates (more details on that in the section below). This species is very territorial and needs to have its own spot in the aquarium in order to feel comfortable.

Red Tail Shark Tank Mates

Because of their potential to be an aggressive fish, it’s important you choose the right tank mates for your Red Tail Shark.

Fish that are overly curious, aggressive, or bottom-dwellers aren’t a good fit for them. They’ll either wander into the Red Tail’s territory or start a fight.

Fish that will mind their own business and spend more of their time in the upper half of the aquarium are compatible. There’s never a total guarantee that you won’t see aggressive behavior, but if you want to keep them in a community tank those are the kind of fish you’re looking for.

Here are some possible Red Tail Shark tank mates:

While it’s definitely possible to keep more than one Red Tail Shark in the same aquarium, it comes with risk. Due to their territorial nature, there’s a high likelihood that these fish will fight unless they have a significant amount of space.

In order to get around this, it’s recommended to have a few of them in the same tank instead of two. However, this also means you’ll need to get a fairly massive tank. That’s why we urge you to avoid doing this and go with other tank mates instead.

Author Note: Fish that look similar should not be kept in the same tank. A great example of this is the Rainbow Shark. There’s something about the red coloration that brings out territorial and aggressive behavior.


There’s not much to talk about when it comes to breeding Red Tail Sharks. These fish are extremely difficult to breed in your typical home tank setup, and there are very few reports of success.

If this changes and someone cracks the code we’ll expand this section. We don’t like encouraging aquarists to try until there’s a clear path of success, so this section will stay blank in the meantime.

Breeding attempts (successful or failed) have an impact on the health of your fish and come with risks. To maximize the wellbeing of your Red Tail Shark it’s better to avoid breeding.


The Red Tail Shark is a stunning freshwater fish that will undoubtedly continue to be popular in the aquarium scene for quite a while.

Their unique look and straightforward care requirements make them a good fit for a wide range of experience levels. The only semi-tricky part of owning one is dealing with their aggressiveness (and that’s only something to worry about if you plan on keeping them in a community tank).

We hope this guide prepared you for Red Tail Shark care and encouraged you to give this species a shot. There’s nothing quite like seeing those bright red spots streak around your aquarium!

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