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Is My Pleco Male or Female? (The Key Differences)

Is My Pleco Male or Female? (The Key Differences)

This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addtion, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

As a new fish owner, determining the sex of fish will be a bit difficult. Sometimes it’s very hard to tell the difference between a male and female fish.

There are certain differences that will make it easier to figure it out. If you’re trying to determine the sex of your plecos, then you’ll want to keep reading.

Below, you’ll learn everything that you need to know about determining the sex of plecos. You’ll learn about how they’re similar and how they’re different.

Even if it isn’t easy to tell which is a male and which is a female at first, you’ll get better at it. Having the right knowledge makes it a lot simpler.

Physical Differences

There are a number of physical differences between male and female plecos. Some differences might be more apparent when you’re looking at specific types of plecos.

You’ll find various types of plecos being sold in pet stores. There are bristlenose plecos, common plecos, zebra plecos, and many more.

The information being presented here is general information about plecos. Just understand that some plecos might have more pronounced differences based on the specific type that they are.

One physical difference to pay attention to involves the bristles of the fish. Many types of plecos have bristles, and the males will grow them from the front of their side fins as well as near the head and mouth.

Certain species will have both the males and females grow bristles. However, the bristles will be much more pronounced and easy to notice when looking at the male fish.

Males often have bristles that cover the head, and they will be longer than normal, too. With female fish that have bristles, they usually just cover the edge of the mouth.

Bristles on Pleco

There are also size differences to consider when looking at the fish. Female plecos are going to be larger than males on average.

If two plecos are the same age, then the female fish is likely going to be bigger. Another way to tell the difference between male and female fish is to look at the shape of the fish.

Female plecos will have bodies that are much rounder overall. Males have thinner bodies.

Looking at the fish from the side will make it easier to tell the difference. You’ll see that the belly of a female fish is substantially rounder.

It’s very easy to tell the difference between male and female plecos when they’re ready to breed. The female will likely be noticeably round.

Another strange difference between male and female plecos has to do with the bony growths on their scales. These fish have bony growths on their scales that are called odontodes.

It’s possible to sex the fish based on where the odontones are located. The presence of odontones on certain portions of the body can indicate that a fish belongs to one sex or the other.

The problem with this is that each type of pleco fish has odontone differences. Therefore, sexing the fish based on odontones will differ depending on the species.

This isn’t an easy way to tell the difference between plecos. In fact, it might even be confusing for people who don’t quite understand what odontones are.

If you want to tell the difference between the male and female plecos, then it’s easier to stick to looking at the size and shape of the fish. These differences will be easy to see with your naked eye.

To get the best results, look at the plecos from the side so that you can see the roundness of the female fish. You’ll have an easy time figuring it out when the fish are of breeding age.

Behavioral Differences

You’ll also want to look at behavioral differences when trying to determine the sex of the fish. Males and females will sometimes have pronounced behavioral differences.

Certain types of plecos are going to be more aggressive than others. In some species, the male plecos will be much more aggressive than the females.

Royal plecos are somewhat aggressive fish, and the males will be far more aggressive than the females. This won’t be a reliable method for determining the sex of many other types of plecos, though.

Royal Pleco

Most plecos are very peaceful, and they’re so docile that neither males nor females will act aggressively. Thus, the aggression differences will only help with semi-aggressive plecos such as royal plecos.

Sometimes males will fight each other a bit, too. Male fish might battle a bit over territory or the right to breed with females.

Sexual Organs

Some types of plecos make it more obvious than others what sex they belong to. Sailfin plecos have sexual characteristics that you can easily see.

Male sailfin plecos have one genital organ that is thick and looks like a stump. Females have a genital papilla that is far smaller.

If you own sailfin plecos, then you should be able to determine the sex of the fish just based on looking for the sexual organs. Of course, the fish need to be mature for you to be able to do this.

Juvenile fish will not have developed enough yet. So long as the sailfin plecos are of the right age, this can be a reliable method for telling sailfin plecos apart based on which sex they belong to.

Final Thoughts

Plecos are really amazing fish to own. Telling them apart based on what sex they are can sometimes be a bit tough.

There are ways for you to determine which fish is male and which is female, though. You just need to pay close attention to how the fish look.

Some pleco fish have prominent differences such as bristlenose plecos and sailfin plecos. Bristlenose plecos have very apparent bristles, and the males will have bristles in more places than females.

You’ll be able to examine the bristles of the fish by simply observing them. If you own bristlenose plecos, then it’ll be rather easy to tell the males and females apart.

Sailfin plecos have differences based on their prominent sexual organs. A male sailfin pleco will possess a single thick genital organ that has a stump-like appearance.

The sexual organ of the female sailfin pleco will be far smaller. Simply looking for the sex organs will give you a reliable way of telling the males apart from the females.

Other plecos can be harder to tell apart. You should still be able to do so by looking at the size of the fish.

Female plecos are larger than males on average. They also have round bodies that will be most apparent when viewing them from the side.

Behavioral differences can sometimes help to tell males apart from females. Male plecos might be more aggressive than females.

Of course, some plecos are so docile that even the males won’t show aggressive tendencies. It’ll be easier to tell males apart from females based on behavior when looking at semi-aggressive plecos such as royal plecos.

You know the differences between plecos now. Use this information to ensure that you know which fish are males and which are females in your fish tank.

Be sure to let any friends know what you learned if they’re struggling with the same questions. It’ll help them to know which fish they have, and that’ll be handy if they wish to try to breed plecos in captivity.

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