Why Is Red Tail Shark Losing Color?

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Red Tail sharks are some of the most beloved tank fish thanks to their temperament, aquatic presence, and adaptability to life in captivity.

This endangered species can no longer thrive in the wild but has no problems adapting to aquarium life, given optimal water conditions.

This brings us to today’s topic – Red Tails losing their color. While this fish is genetically sound, it is not safe from the common aquatic diseases that plague most fish species. But it’s not only parasites and bacteria to worry about.

Your Red Tail can face several health problems of different natures and will always display warning signs.

A sudden change in coloring is the first symptom that something is not right.

Reasons Red Tail Shark Is Losing Tail Color

First, let’s understand what a healthy tail coloring looks like. Red Tail sharks come in various colors but will always retain a similar pattern.

Their body is usually one color, while the tail fin is another. Red Tail sharks are mostly black or dark blue with bright red or orange tail fins.

However, the tail’s color, intensity, and color pattern may vary. Some sharks display blood red, others light orange, others have some brown hues visible, while some sharks have transparent-red fins.

The problem occurs when your Red Tail begins to change its tail color that was present up to that point.

There are several reasons for that:


The most noticeable fish diseases your Red Tail faces are Ich and fin rot. It’s not to say that they cannot struggle with other disorders, but these 2 are the most common.

Each disease will come with slightly different symptoms, but some will be common.

These including:

  • Lower appetite or refusing food
  • Lethargy and spending too much time immobile or exhibiting little swimming
  • Difficulty maintaining buoyancy or body posture
  • Irritability and increased aggression for no clear reason, etc.

Changes in body and tail coloring are also common in these situations, hinting at the fish experiencing severe distress.

When that happens, you should act immediately. Most fish disorders are deadly when untreated and will aggravate fast.

Whether it’s Ich, fin rot, swim bladder disease, or any other condition, quarantine is the first necessary step. Place the Red Tail in a hospital tank and make sure that the water parameters remain in the ideal range.

The treatment necessary will vary depending on the disease’s profile, how severe and advanced it is, and the fish’s age and overall health.

Your Red Tail should begin to recover within a couple of days with adequate treatment. If it doesn’t, I recommend euthanasia to end its suffering and prevent the disease from spreading to other tank occupants.

Water Conditions

Red Tails prefer living in optimal water conditions. While they do accept some variation in their water parameters, too many or too frequent fluctuations will hurt them.

You want your Red Tail’s habitat to remain clean, fresh, and comfortable 24/7, which requires regular maintenance and cleaning.

Here are some useful tips to use for a 55-gallon tank with one Red Tail:

  • Have a reliable filtering system – The filter should offer biological, chemical, and mechanical filtration. If one filter isn’t enough for the 55-gallon tank, or you wish to keep the water currents low without cutting on the filtering efficiency, have 2 filters. A dual-filter system will provide double the benefits. Just make sure that the water currents remain low, not to disturb your Red Tail.
  • Water changes – The official recommendation is to change your Red Tail’s water every week. However, I would say that this only applies to small tanks below 30 gallons and tanks containing several fish. One 55-gallon tank housing one Red Tail won’t need water changes as frequently. Especially since the Red Tail isn’t a particularly messy fish and thanks to its feeding pattern. The Red Tail will feed on environmental algae and organic matter, doing much of the maintenance work for you. One partial water change every 2-3 weeks should suffice for the most part.
  • Monitor water parameters – No matter how clean the water might look like, always monitor your tank water parameters. You never know when temperature, pH, or ammonia levels could fluctuate, causing your Red Tail to experience immediate discomfort. Sudden variations in water conditions could cause thermic or osmotic shock that could kill your fish.

Seeing how Red Tails aren’t exactly the most chill fish, so you need all the help you can get to keep their temperament in check.

And to preserve its health long-term. Controlling its water parameters is one of the best ways of achieving that.

Ammonia Poisoning

Ammonia poisoning is usually deadly, which is why prevention is key. Fortunately, your Red Tail won’t create as much mess as other fish, especially since it will be alone in the tank.

And because Red Tails consume organic matter and algae as bottom feeders, contributing to a cleaner and more stable environment. That being said, ammonia can still spike out of control in some cases.

One of them is due to ignoring the importance of regular tank maintenance and water changes. Red Tails will produce waste which will accumulate with time and change the water chemistry in the process.

It doesn’t take much ammonia to cause your Red Tail to experience significant health problems.

Another common reason for ammonia spikes is not performing weekly water changes in community tanks. While Red Tail sharks prefer to live solitary lives, they can adapt to living in a community aquarium.

Most aquarists pair Red Tails with cichlids, which are famous for their messy behavior. Cichlids will poop a lot, and they are messy eaters, increasing the risk of dangerous ammonia buildups.

A cichlid tank requires weekly 10% water changes to preserve the system’s stability and prevent ammonia problems.

If your Red Tail shows signs of ammonia stress, you should fix the problem immediately. Ammonia poisoning is a deadly condition that will kill your shark fast.

Chlorine Poisoning

Chlorine poisoning is also quite common among novice and inexperienced hobbyists who are unfamiliar with the dangers.

This condition occurs mostly during water changes or when cleaning the tank equipment, and it’s due to people using tap water. Tap water is almost always chlorinated.

Chlorine is a chemical that water authorities use to sterilize the water and make it drinkable for humans.

The problem is that chlorine is like poison to Red Tails and fish in general. Even small amounts could lead to chlorine stress and poisoning, which are fatal.

The Red Tail will immediately display signs of stress when in the presence of chlorine, one of which includes color changes. When that happens, you should act immediately.

Quarantine the fish in a hospital tank, measure the chlorine levels in the main tank, and use a dechlorinator to remove the chemical. You should also perform a water change following the procedure.

Your Red Tail should recover fairly fast with adequate care, which includes a nutritious diet, clean water conditions, and stable temperatures.

Even more important than the treatment is to prevent the situation in the first place. Never use tap water during water changes or to clean the tank’s filter or any equipment until you’ve dechlorinated it first.

You can achieve that either by using a dechlorinating solution or boiling the water, which will force the chlorine out.

Either that or use other types of water, like RO/DI. When cleaning the tank equipment, use tank water in the process.

Incorrect Diet

Red Tails aren’t too pretentious about their diets, but they do require adequate feeding to remain healthy in the long run. Not providing them with adequate food and a regular feeding pattern can affect their biology.

Red Tails need an omnivorous diet, and you should feed them around once every couple of days. They will get the rest of their food from their environment.

If their habitat isn’t too rich in food sources, you might want to feed the shark more often.

Make sure the shark receives adequate nutrition, otherwise, it may experience vitamin or mineral deficiencies. These are deadly in severe cases and when lacking proper measures.

Aggressive Mates

The general rule is always to pair Red Tails with more aggressive and territorial fish. Otherwise, Red Tail sharks will end up bullying the calmer and more pacifying species.

More aggressive tank companions, like cichlids, will stand their ground and put the Red Tail in its place. It’s why most people will pair the Red Tail with cichlids.

The secret is to keep the aggression under control. If their tank mates are too big, territorial, or display bullying behavior, Red Tails may suffer the consequences. They might become stressed and remain in hiding out of fear of getting out.

Such a lifestyle will eventually affect them and will influence their temperament, behavior, coloring, and health.

To circumvent this issue, choose your Red Tail’s tank mates carefully. I would stick to medium-sized, semi-aggressive cichlids like Red Cap, Ruby Red Peacock, or Blue Neon, among others.

Some African cichlid species are also compatible with the shark, provided they fit the required parameters.

The cichlids should be between 5 to 8 inches long, which is enough to prevent any predatorial behavior or bullying on both fronts.

As general rules, make sure that the Red Tail’s tank mates:

  • Match the shark in aggression and territorial behavior
  • They are of similar size (around 6 inches, give or take a couple of them)
  • Don’t share the same living space

Regarding to the last point, since Red Tails are bottom-dwellers, avoid bottom-dwelling tank mates to prevent a potentially deadly conflict of interests.

And, whatever you do, never keep more than 1 Red Tail shark in the same aquarium. That is, unless the tank is huge, preferably beyond 90 gallons, and has multiple hiding spots.

Even so, you can’t be sure that your Red Tails won’t stumble across each other and won’t fight to the death. This tends to happen a lot between Red Tails due to their extreme territorial behavior towards one another.

Why is Red Tail Shark Turning White?

There isn’t one cause for your Red Tail turning white. Water conditions are to blame in most cases, along with stress and even disease.

A common problem in this sense relates to Red Tails living in cichlid-oriented tanks, and it’s because of the pH differences. Red Tails require a pH level between 6.0 and 8.0. Cichlids, however, need a pH between 8.0 and 9.0.

If your Red Tail doesn’t tolerate the cichlid-specific pH, you might want to look for a fix fast. Suboptimal pH levels could stress out and even kill your shark in the long run.

If the pH has nothing to do with it, look for signs of stress, and disease and verify water parameters.

The problem has to fall in one of these categories, and identifying the problem will automatically inform you of the correct response.


The conclusion is pretty straightforward – Red Tails don’t change their color on a whim, unlike other fish species.

If they do begin to display changes in coloring, something’s not right.

This article has provided you with the knowledge and tools to correct the problems fast and effectively.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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