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How Big Do Red Tail Sharks Get? (And Why They Stop Growing)

How Big Do Red Tail Sharks Get? (And Why They Stop Growing)

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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.

Red-tail sharks can make your aquarium more lively and fun. They’re feisty, unique fish that swim around the bottom of the tank most of their time.

More importantly, people love to keep them as they strongly resemble sharks. However, they aren’t closely related to sharks, as the name might suggest.

In fact, they are part of the Cyprinidae family, which makes them more related to carp fish than sharks.

Before adding these tiny sharks to your tank, you might be wondering, how big do red-tail sharks get? And do they need a special tank?

Look no further for the answers! In today’s article, we’ll tell you everything you need to know about the size of these feisty creatures.

Their Max Size

Red-tails, also known as Epalzeorhynchos bicolor, are freshwater sharks, which means they’re different from marine ones.

Therefore, they don’t grow to be as big as marine sharks. Typically, the size of a fully grown red-tail shark doesn’t exceed 6 inches, which makes them medium-sized fish by aquarium size standards.

However, their size isn’t the main indicator of how large your tank should be. Although they aren’t gigantic fish, red-tail sharks require a large tank to roam around freely.

So, they don’t do well in crowded tanks. Generally, these tiny sharks tend to be aggressive and territorial.

Do Red Tail Sharks Need a Large Tank?

The answer is yes. Red-tail sharks have feisty, semi-aggressive personalities. To add, they are highly territorial and can harass any intruder relentlessly.

Luckily, you can avoid territorial issues by putting them in a large tank containing plenty of hiding spots. Adding ornaments and decorations to the aquarium can further reduce the aggression levels of the sharks by creating visual barriers between them and their tankmates.

Ideally, you need at least a 55-gallon tank or bigger to host one red-tail shark. I found that tanks between 75 and 100 gallons are the best to lower aggression levels.

How Fast Do Red Tail Sharks Grow?

When provided with optimum conditions, red-tail sharks can be fast growers. They can reach their maximum size in a little over a year.

In most cases, red-tails are sold as juveniles. At that age, they’re usually around two to three inches long. Throughout their first year, they can reach approximately five to six inches.

However, this mainly depends on the conditions they’re living in. Providing them with a balanced diet and adequate care is essential for their growth.

How Long Does It Take for a Red Tail Shark to Be Fully Grown?

It takes a red-tail shark a little over a year to reach its maximum size of six inches. Additionally, some fish take up to two years to reach their full size.

Further, if you don’t provide your fish with the optimum conditions it needs, it might not reach its maximum size.

Why Is My Red Tail Shark Not Growing?

Many reasons can cause your red-tail shark not to grow as it should. Let me tell you about them and how to overcome each issue.

1 – Unsuitable Water Parameters

Although red-tail sharks aren’t the most sensitive fish, you need to monitor the water condition.

Ideally, the water temperature should be around 72 °F to 79 °F. Additionally, it’s best to keep the pH levels between 6.5 and 7.5, while the water hardness should be about 10-15 KH.

Generally, we recommend investing in an aquarium testing kit. Moreover, you need to check the water parameter regularly.

2 – Incompatible Tank Mates

Red-tail sharks are picky about their tank mates. They tend to be territorial and chase other fish around the tank.

In turn, this can cause stress to the sharks and the other fish, which causes delayed growth.

When picking tank mates for red-tail sharks, you want to choose large-bodied, less aggressive fish species.

Further, they should be mid or upper levels swimmers. That’s because red-tail sharks swim in the lower levels of the tank.

More importantly, the fish should be less aggressive and faster swimmers. That said, here are some examples of fish that can live peacefully with red-tails:

1 – Diseases

Red-tail Sharks are prone to some diseases that can delay their growth. That includes ICH and fin rot.

Many freshwater fish are prone to ICH. The disease is caused by the parasite Ichthyophthirius multifiliis.

Luckily, ICH is easily distinguished by the white, salt-like spots that appear on the fish. In case your fish has ICH, you need to quarantine it in a separate tank and contact your vet.

On the other hand, fin rot is mainly caused by poor water conditions. You can tell your fish has fin rot when the base of the fin is inflamed or if there’s any discoloration on the shark’s body.

Generally, to keep your fish healthy, you want to provide them with a clean, safe environment. To do so, you need to perform regular tank maintenance and water changes. Additionally, you want to provide your fish with a healthy balanced diet.

More importantly, you should take your fish to the vet as soon as possible if you notice any of the following symptoms:

  • Difficulty breathing
  • Discoloration on any part of the body
  • Swimming slower than usual
  • Not eating
  • The edges of the fins look frayed

2 – Not Enough Space

As we’ve mentioned, these feisty sharks are territorial. Therefore, they don’t tolerate having any intruders in their territory.

Overall, red-tail sharks don’t do well in small or crowded tanks. It can be such a stressful situation for them, and it can affect their growth.

They need room to roam and establish their territory. Ideally, you don’t want to put them in a tank that’s smaller than 55 gallons.

The larger the tank is, the better it is for the sharks.

1 – Unbalanced Diet

One of the most common causes of health issues in red-tail sharks is an unbalanced diet.

Generally, they’re omnivores, so they aren’t picky about their food. In the wild, they mainly feed on plants, crustaceans, and small insects.

In addition, they tend to scrape food from hard surfaces in their environment, like rocks, driftwood, and other aquatic elements.

Ideally, you want to feed them a high-quality, balanced diet that contains plant-based and animal-based foods.

For plant-based food, many growers recommend adding zucchini medallions, shelled peas, and cucumber medallions. Generally, you want to make sure that the vegetables are washed thoroughly before giving them to your little sharks.

Moreover, many commercial shark food brands are suitable for your red-tail fish. They can provide your fish with all the vitamins and minerals they need to remain healthy and grow.

More importantly, you need to feed your fish once every other day. What’s more, you need to remove uneaten food from the tank.

2 – Fish Stress

If your little sharks are stressed, they become more prone to disease. That’s because stress can weaken their immune system.

Additionally, they might not grow to reach their maximum size. Therefore, you want to avoid anything that can make your sharks stressed. That includes the following:

  • Sudden pH changes
  • A big change in water temperature
  • Living with other aggressive fish
  • Not enough space to roam
  • Poor diet and competition
  • Not enough decorations or ornaments in the tank
  • Poor water quality
  • Lack of oxygen in the water
  • Diseases

Why Did My Red Tail Shark Stop Growing?

Some red-tail sharks might need around two years to reach their maximum size. Additionally, while most red-tails grow up to six inches, some of them will remain around four inches tall.

Sharks’ genetics can also influence their maximum size. So, if the parent sharks weren’t big, their offspring probably won’t grow any bigger. In other words, your fish might’ve already reached its maximum size.

For that reason, make sure to buy your red-tail sharks from a reputable breeder. In addition, you can ask the breeder to see the parents and check their size.

Chances are, the offspring will reach the size of the parents. Overall, as long as you’re providing the fish with the optimum conditions, there’s nothing to worry about.

Should You Add Red Tail Sharks to Your Aquarium?

If you’re looking for a fish that adds liveliness and fun to your aquarium, red-tail sharks are for you. However, they aren’t the easiest to take care of, and they don’t do well in small tanks.

Further, the tank should have enough hiding spaces, plants, and ornaments. Any decorations can help lower the aggression levels of the sharks.

Overall, red-tail sharks aren’t the best option for beginners, especially if you’re planning to add other fish to the aquarium.

Is There a Size Difference between Male and Female Red Tail Sharks?

The answer is no. Male and female red-tail sharks are almost identical in size. In fact, many growers find it hard to distinguish between males and females.

However, females tend to have bigger, more rounded abdomens due to their reproductive system.

Final Thoughts

So, how big do red-tail sharks get?

Red-tail sharks are considered to be medium-sized fish by aquarium standards. On average, they can grow up to six inches if you provide them with a balanced diet and suitable water parameters.

Although they aren’t large, red-tail sharks require a big tank. That’s because they’re semi-aggressive and highly territorial.

Additionally, they tend to chase intruders around relentlessly. For that reason, you want to put them in a tank that’s at least 55 gallons large.

Moreover, there are many reasons that can cause your sharks to not reach their maximum size. That includes unsuitable water parameters, incompatible tankmates, diseases, small tanks, and an unbalanced diet.

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