Red Tail Shark Size: How Big Do They Get?

The Red Tail Shark is a tropical, freshwater fish native to Thailand. Known for its vibrant red tail and sleek, black body, this fish adds beauty to any home aquarium. Despite the name, it’s not actually a shark but is rather part of the Cyprinidae family.

red tail shark size

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What is the Average Size of Red Tail Shark?

The average size of a Red Tail Shark can be quite surprising to many as these fish tend to grow quite large. Conventionally, the size ranges from 4 to 6 inches (10.2 to 15.2 cm) when the fish are fully mature.

  • On most occasions, a Red Tail Shark will grow as long as 6 inches (15.2cm).
  • However, the nature of their growth tends to be slightly unpredictable.

It’s not unusual for some Red Tail Sharks to even surpass this limit and reach up to 7 inches (17.8 cm) or might even expand to a stunning 8 inches (20.3cm), making them an impressive addition to any aquatic environment. Hence, when accommodating a Red Tail Shark in an aquarium, their potential growth size must be kept in mind to ensure a healthy living condition.

  • The unique aspect of Red Tail Sharks is their growth variability.
  • Make certain you provide them with ample space to grow and swim.

The exact size of your Red Tail Shark can greatly vary and depends on numerous factors such as diet, environment, and overall health. However, on average, you can typically expect your shark to reach somewhere between 4 to 6 inches in length, with the potential to grow even larger.

Remember – every Red Tail Shark is unique. Your fish might grow more or less than the average size. Give it the utmost love and care and enjoy its growth journey.

What is the Growth Rate of Red Tail Shark?

When it comes to the growth rate of the Red Tail Shark, it’s key to have a clear understanding. Like most fish species, the Red Tail Sharks grow quite rapidly in their initial stages after hatching.

  • Their growth rate, however, might slightly slow down as they journey towards adulthood.
  • This slowing down usually happens when they’ve attained around half their full size.
  • Often, within the first year, they’ll reach about 60% of their full length. That’s between 2.4 to 3.6 inches.

Now, you may wonder, “How quickly do they get to the full size?” Here’s what you ought to know:

  • For most Red Tail Sharks, they’ll hit the 6-inch mark within a time frame of 2 to 3 years.
  • These estimates can vary based on a range of factors like diet, habitat, and overall health.

By “2 to 3 years”, I mean that in most cases, Red Tail Sharks will reach their length of about 6 inches (15.2cm) when they reach the age of 2 to 3 years old.

But don’t be surprised if you see a few sharks that overshoot this average size. As mentioned earlier, some sharks can get to 7 or 8 inches (17.8cm to 20.3cm) in length.

Overall, their growth rate is quite fascinating, isn’t it? However, do remember that they may need your support during their growth process in terms of nutrition and habitat.

Are There Size Differences Between Male and Female Red Tail Sharks?

There’s a common question, and that is whether there are differences between the sizes of male and female Red Tail Sharks. The answer is no.

To lay it out simply:

  • No noticeable size difference exists between males and females.
  • Both sexes typically reach a length of 4 to 6 inches when fully mature.

Species’ physical variance often lies in aspects other than length. For the Red Tail Shark, sex differentiation is better recognized by analyzing the anal fin or color variations.

Both males and females share the characteristic red tail, with males occasionally exhibiting a darker body coloration.

  • Males: Distinguishable by their pointed anal fins.
  • Females: Display noticeably rounder anal fins.

It’s also important to note that environmental elements such as diet and habitat size can influence the growth of the Red Tail Shark, regardless of sex.

Given this:

  • Optimal conditions ensure each Red Tail Shark attains its maximum growth size, irrespectively.
  • While domesticated, Red Tail Sharks kept in cramped spaces or underfed may experience stunted growth.

Don’t rely on size as an identifier between sexes. Instead, focus more attention on the shape of the anal fin and color gradients.

In the wild or captivity, both male and female Red Tail Sharks hold the potential to reach lengths up to 8 inches (20.3 cm) under optimal conditions. A practical aspect to keep in mind when planning to home this fascinating species.

When Do Red Tail Sharks Reach Full Size?

Knowing when Red Tail Sharks reach their full size is crucial to your understanding as an aquarist. Contrary to what you may think, these sharks don’t grow overnight.

Typically, Red Tail Sharks reach their full size between 1 and 2 years of age. Yes, you heard that correctly. In just a short time, they transform from younglings into mature, full-grown individuals.

Don’t expect linear growth, though. Often, the biggest growth spurt occurs when the shark is between 6 and 12 months old. During this period, feeding and tank conditions are especially important.

From one day to the next, you may not notice considerable differences in your shark’s size, but to see this transformation in a year or two is truly a sight to behold.

Remember, each Red Tail Shark is unique. Some may grow quicker than others, so don’t be alarmed if the growth rate of your Red Tail Shark doesn’t exactly match the timeline mentioned.

It’s important to mention that reaching full size too quickly could indicate an unhealthy diet or environment. Overfeeding or high-stress levels could lead to untimely growth spurts, which may cause health issues.

What Factors Influence the Size of Red Tail Sharks?

Various factors play integral roles in determining the final size of a Red Tail Shark.


The size a Red Tail Shark reaches is directly influenced by the living environment. A larger tank equates to a larger growth space for them. Therefore, for optimal growth, please ensure:

  • Tank Size: Red Tail Sharks require at least a 55-gallon tank. Anything smaller might stunt their growth.


Food also plays a paramount role in affecting their growth. Varied, nutrient-rich diets foster healthier, larger Red Tail Sharks.

  • Protein intake: Sharks, being omnivorous, thrive on a balanced diet – lean protein, vegetables, and special fish flakes.


Lastly, genetics causes variances in their sizes.

Obviously, you can’t influence genetics of your Red Tail Shark, but it’s worth noting that this factor does play a role in their size.

How do Red Tail Sharks Compare in Size with Other Species?

When it comes to the subject of size, Red Tail Sharks exhibit a distinct difference in comparison to many other species in the aquatic world. These freshwater species generally range from 4 to 6 inches (10.2 to 15.2 cm), with an occasional reach up to 8 inches (20.3 cm), as previously discussed. Now, let’s see how they fare among other species.

  • Guppies – These species are relatively small and only grow to about 2.5 inches (6.4 cm) at most. This makes them much smaller than the Red Tail Sharks.
  • Goldfish – Depending upon their type, goldfish can grow from 1 foot to 2 feet (30 to 60 cm) in length. This places them significantly larger than Red Tail Sharks.
  • Betta Fish – Betta fish, also known as Siamese fighting fish, typically grow up to 3 inches (7.6 cm) in captivity. Here, Red Tail Sharks are larger.
  • Angelfish – Angelfish are known to reach up to 10 to 12 inches (25 to 30 cm) in height and 6 inches (15 cm) in body length. They find themselves in the same ballpark as Red Tail Sharks in terms of body length.

From this comparison, it’s apparent that the size of the Red Tail Shark is somewhat in the middle. They are larger than guppies and betta fish, but smaller when compared to goldfish and angelfish. It’s clear that the Red Tail Shark’s size varies quite dramatically from one species to another, reflecting the broad diversity in the aquatic world.


We’re at the end of our in-depth look at Red Tail Shark sizes. It’s fascinating how they grow and compare with other species, don’t you agree? We’d love to hear your thoughts and experiences in the comments below.

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