How To Tell If A Discus Fish Is A Male or A Female?

How To Tell If A Discus Fish Is A Male or A Female?

Do you want to breed discus fish? Or are you just curious about the gender of your discus fish? Either way, it’s important to be able to tell male and female discus fish apart.

Although it can be difficult to tell the difference between male and female discus fish, there are a few key characteristics that you can look for.

For example, male discus fish tend to be larger than females. Also, males tend to be more aggressive than females and may chase other fish around the tank.

This is not the only thing! In this article, I’ll go through every aspect of discus fish differences, from their looks to their behavior.

How to Sex Discus Fish?

As they grow, the males and females start to develop different physical and behavioral characteristics. To help you tell them apart, here are some of the main ways to sex discus fish:

Behavioral Characteristics

Pairing  Up

Discus fish are known to be very social creatures. In the wild, they live in large groups and form complex relationships with one another.

In captivity, discus fish will often pair up with other fish of the same species. When it comes to pairing up, males are usually much more aggressive and will often chase other fish around the tank.

On the other hand, females are very passive and typically remain in one area of the tank. Thus, the male will try to induce her to move by chasing her around.


When there is more than one male in the tank, they will often fight with each other for dominance. They might even nip at each other’s fins and tails.

In contrast, females rarely fight with each other. They are much more docile and tend to get along well with other fish in the tank.

Physical Characteristics

Color Patterns

This one can be pretty obvious once you know what to look for. Male discus fish tend to have darker and more color patterns than females.

However, females tend to be a little brighter in color with less intense patterns. During spawning, the male’s colors will become even more intense to attract the female.

Eye Color 

The discus fish of the same strain have distinct coloring in their outer eye-rings depending on gender. Typically, males have darker and more colorful irises while females have comparatively lighter and less pigmented ones.

Body Size 

Males are typically larger than females. Also, the males have bigger forehead bumps and their bodies are more muscular. In my opinion, this is the most reliable way to tell male and female discus fish apart.

Lip Sizes 

Males have bulged-out lips that are significantly larger than females. They use these lips to lock and engage in fights with other males to establish dominance over their territory.

Dorsal Fins 

For male discus fish, the dorsal fins are usually longer and more pointed. However, females have shorter and rounder dorsal fins.

Fins Arrangement 

This method is 100% reliable but requires a bit more experience. In the male’s case, if you draw an imaginary line from the tip of their dorsal fin to the ventral fin (belly), you will notice that the line touches the outer end of the tail.

However, if you do the same for a female, the line will brush against the outer side of the tail.


Breeding Tube 

The breeding tube is located on the underside of the discus fish, just in front of the vent. The female breeding tube is longer than the male breeding tube.

Egg Laying 

Of course, the most obvious way to tell if your discus fish is female is when she lays eggs! Shortly after mating, the female will start to lay her eggs. Once you see the eggs, it’s pretty much a guarantee that your fish is female.


How to Care for Discus Fish?

Discus fish are relatively easy to care for as long as you provide them with a large tank, plenty of hiding places, and clean water.

How Big Do Discus Fish Get?

Discus fish can grow to be about 7-9 inches in length.

Why Do Discus Fish Pair Up?

Discus fish typically pair up in order to reproduce. The male will chase the female around until she lays her eggs, and then he will fertilize them.

Do Discus Fish Need to Be in Groups?

Discus fish need to be in groups in order to feel comfortable and secure. They are social creatures that thrive in the company of others.

What Do Discus Fish Eat?

Discus fish primarily eat meaty foods such as brine shrimp, and bloodworms. Also, they need to have a variety of vegetables in their diet, such as spinach and zucchini.

How Often Should I Feed My Discus Fish?

You should feed your discus fish 2-3 times a day. Each feeding should consist of small amounts of food that the fish can eat in 5 minutes or less.

Last Words

Telling the difference between male and female discus fish can be tricky, but it’s definitely possible. By looking at their physical and behavioral characteristics, you should be able to tell them apart with ease.

Just remember, male discus fish are usually darker and more colorful, have bigger lips, and have longer dorsal fins. On the other hand, females tend to be brighter in color, and have shorter dorsal fins, and a longer breeding tubes.

Do you have any other tips on how to tell if a discus fish is male or female? Let us know in the comments below!