Do Fish Shed Their Scales?

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Today we’ll talk about a subject that many fish owners are interested in: do fish shed their scales? If you own an aquarium yourself, maybe you’re asking the same question about your fish.

Have you seen your fish loose some of its scales? Or even a lot of them? If yes, then what is the cause behind it? Is it normal? Can it be prevented in any way?

Let me answer the question right away: NO, fish do not shed their scales, in normal conditions. They don’t have to do such a thing.

If you’re thinking that some fish shed their scales because they are growing bigger, that is a total misconception. Actually, if nothing bad happens in their environment, your fish will never shed their scales. They need them to live a healthy life.

Some people think that fish are similar to snakes in this regard. Snakes do shed their skin. But this is a misconception, that isn’t true at all in the fish world.

But if that’s the reality, why do some fish shed their scales? Read on to find out! One of the reasons below could be true in your case as well.

Reasons Why Fish Is Shedding Its Scales


Reasons Why Fish Is Shedding Its Scales

There could be multiple reasons why your fish might shed scales. But we’ll talk about the 2 most common reasons. If you see your fish shedding some scales, it’s quite likely that one of these is true in your case. Let’s see:

Physical Damage

This is the first cause for scale shedding. How does it happen? For example, many species are very active during their breeding period. When this happens, they brush up themselves to many objects present in the tank. Thus, resulting in physical damage, that shows mostly in lost scales.

Another common cause for physical damage is the aggressive behavior of certain fish that are present in the tank. Such fish could harm the others by hitting them constantly. This can also result in lost scales, mostly on the fish that was attacked.

It’s best to not keep very aggressive fish together in the same aquarium with peaceful ones, to avoid such behavior. Also, sharp objects are not to be kept in the aquarium, to prevent scale loss.

This doesn’t mean that you can’t add decorations or caves inside the tank. in most cases, these present sharp parts. But make sure you prevent your fish from hurting themselves with these objects.


An infection can also cause your fish to shed its scales. This is the second most common reason. There are many different infections that can appear in a home aquarium. However, there is a specific disease that results heavily in scale loss and it’s called just like that: scale shedding. Another name for it is infectious protrusion (you’ll soon know why).

Scale Shedding Disease

This infection is caused by certain bacteria, and if you don’t treat it, it could prove to be fatal for at least some of the fish in your aquarium.


What are the symptoms? In first stages, your fish might look healthy, but you can witness some protruding scales on its body. Later, these will likely grow in number. Under these scales, small bubbles are forming that contain a serous fluid.

These bubbles are forming exactly where the scales are attached to the body of the fish. Because of this, these scales will be shed and results in other bad consequences.

Due to the scale loss and bubble forming, your younger fish will have problems breathing. That’s because at this stage in their life, fish are breathing through their “skin”, and thus the protrusions are preventing them from it.

However, these symptoms are not always a precursor to Scale Shedding. To be exactly sure the disease is present in the aquarium, you should have a scale examination, together with the tissue that surrounds it.


To treat this disease efficiently, you have to know about its presence in the early stages. Otherwise, you can’t cure your fish. If the disease is already resulting in heavy scale loss, those fish can no longer be cured. But if you spot the disease early, you can treat it efficiently. How?

You can use Basic Violet K to treat the sick fish. This is to be done in a separate aquarium, to protect the others, that are still healthy.

Also, there are certain antibiotics that can prove to be effective against the Scale Shedding. For instance, you can use Bicillim-5, Biomycin and Sulfanilamide. Any of the 3 mentioned is effective against this disease.

While you treat your fish, you must also clean the aquarium where the disease happened. To do this, use 5 percent of Sulphuric acid, Chloramine or Hydrochloric acid solution. The gravel must also be disinfected. A good method for this, is to boil it to make sure all bacteria are removed.

If you have plants in the aquarium (quite likely), you have to disinfect those as well. Treat them with Bicillin-5 solution.

Now that you know why a fish could shed its scales and how you can prevent it, let’s see if they can grow back those scales or not. I will also answer a common question about a certain fish breed later on.

Can Fish Grow Back Their Scales?

In most cases, yes. If your fish lose even a larger number of its scales, they can grow back normally. However, depending on different breeds of fish, it can take different periods of time to grow them back.

For instance, some fish will grow back the shed scales in a matter of weeks. Others could even take up to 3 or 4 months. It really depends on the fish you own.

However, in certain cases, they won’t grow them back. For instance, if they lost too many scales already, there’s a higher chance they won’t grow them back. Or at least not all of them. This mostly happens when they lose scales because of the infectious protrusion disease.

But if your fish will get healthy again, the scales should grow back, most of them anyway. For that to happen though, be cautious and do everything by the book. This way, you can do all that’s necessary to help your fish get healthy and look as good as new.

Can Pleco Fish Damage the Scales of Other Fish?

There are many different types of pleco fish. But it’s quite common with most types, that they attack or just simply disturb the others in the tank.

For instance, they have a “special” relationship with Goldfish. Plecos are known to suck off the slime coat off from Goldfish. Mostly, this results in scale shedding on the part of the Goldfish.

When this happens, the Goldfish will lose its protective covering, and it becomes more vulnerable to the Plecos and other outside factors.

Plecos are also known to attack Goldfish directly. This also results in scale loss and even the splitting of the Goldfish’s tail.

There are other species too, that feel uncomfortable with Plecos around them. To find out which fish don’t like Plecos, just do a quick online search. It can prove quite helpful, so you don’t mix together species that will potentially hurt each other.

When keeping Plecos in your aquarium, make sure you have tank mates who don’t have grudges against them, or the other way around. This way, you’ll prevent your fish from losing scales or even getting killed (yes, it happens).


In this article we talked about fish scale shedding. Usually, fish do not shed their scales for no reason. And it doesn’t have to do anything with growth.

I mentioned above two of the most common causes for scale shedding: physical damage and infections. You can prevent both of these, if you take the necessary precautions.

Be especially alert when you notice an infectious cause for scale shedding. If the disease already begun, you can cure your fish if you notice the infection in its early stage. Unfortunately, the fish that already lose many scales when you notice the disease, can’t be cured anymore. Don’t forget to disinfect the whole environment after such a disease took place.

It’s true, fish can grow back scales, as you could see from above. But it’s best to prevent the shedding in the first place, so you don’t have to worry about this problem at all.

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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