How to Tell If Angelfish Is Male or Female?

Sexing your Angelfish isn’t necessary, but knowing this information can be helpful. Knowing whether a fish is male or female will come in handy when you’re trying to breed your Angelfish or minimize aggression in the tank.

For example, male Angelfish tend to be more aggressive with one another. It’s best to keep a higher ratio of female to male fish if you want to avoid fights between males. Similarly, you’ll need to be able to select a breeding pair correctly if you want to achieve successful spawning.

If you need to sex your Angelfish for these particular reasons, or any other reason, keep reading. In this article, I’ll cover everything you need to know to tell your male and female fish apart. So, let’s get started!

Male vs Female Angelfish – How to Tell the Difference?

It’s a bit difficult to sex Angelfish compared to other species. That’s because male and female Angelfish come in the same colors and patterns, unlike Guppies, for example. In Angelfish, sexual dimorphism is less apparent.

At a first glance, both male and female fish look roughly the same. However, there are still some subtle differences. Knowing how to spot them will make sexing your fish a lot easier. Here’s what to look out for:

– Angelfish Size

Starting with the most obvious trait! This is the first thing you notice when comparing two otherwise similar fish. Angelfish males are noticeably larger than the females. Their bodies appear both longer and taller.

This usually applies to most egg-laying species, by the way. If you’re going off size alone, sexing Angelfish is easiest when you have fully-developed adults. However, the size differences become apparent early on during development.

Male fry and juveniles grow faster than females regardless of diet quality and living conditions. So, if some of your young fish are larger than others, there’s a high likelihood these fish are male.

– Body Shape

Body shape also differs between male and female Angelfish. This distinction is subtle but very important. Males have circular bodies. They have rounded foreheads and backs. Their foreheads appear round because of a small nuchal hump, which is missing in females. In comparison, female Angelfish have more angular bodies.

The lack of a nuchal hump results in a sloped forehead appearance. Similarly, female fish have less curved backs. When seen from the side, female Angelfish have a more defined body shape given the wider angle of the head and back. Male Angelfish look more like flattened pancakes, for lack of a better comparison.

– Fin Shape

Here, I’m talking specifically about the ventral fins. If you’re not sure where the ventral fin is, it’s the first fin on the fish’s belly; the one furthest away from the tail. In Angelfish, this fin is thin, long, and split into two. If you look closely, you’ll notice some subtle differences here too.

In males, the ventral fins have a rougher appearance. They’ve got forked outer edges and might look prickly. In females, the ventral fins appear rounded and smooth with no splits. Females also have shorter ventral fins than males. This results from body size differences. Remember, the ventral fins are proportional to the fish’s body size!

– Belly Shape

Male Angelfish have round-looking bellies. In contrast, female Angelfish have more straight-lined or angular bellies. This is pretty uncommon for most species, as it’s usually the females that have softer, rounder-looking bellies. The only time you’ll see a rounded belly in a female Angelfish is when she’s carrying eggs.

But even then, it’s easy to distinguish between male and female bellies. If a female Angelfish is carrying eggs, her belly will look disproportionately big compared to the rest of her body. Also, the belly will appear swollen when seen from the front. Male bellies, although rounded when seen from the side, don’t stick out when seen from the front.

– Vent Shape and Size

All fish have a vent. This is an opening on the fish’s body and is located between the anus and the anal fin. The vent serves multiple purposes, including the release of either eggs or milt (fish sperm) during breeding. Because of this, you’ll often see the vent referred to as a “breeding tube” in Angelfish.

Again, there are marked differences between male and female vents. But these only become apparent once the fish are fully mature. If you take a closer look, you’ll notice that male Angelfish have a smaller vent. In males, the vent is narrow and pointy. In females, the vent is more easily noticeable because it’s wider and has a blunt shape.

– Behavior

Finally, we have behavioral differences. These aren’t always reliable, because a fish’s behavior can be influenced by multiple factors such as stress, tank mates, aquarium size, and more. But overall, some tendencies hold true in a majority of cases.

The main thing to know is that male Angelfish are more territorial, hostile, and aggressive. This behavior becomes most apparent during breeding time. Male Angelfish become very competitive, especially when there aren’t enough female fish around.

If you notice an Angelfish chasing, biting, or bumping into other Angelfish, or other species in the tank, it’s most probably a male. Female Angelfish can also become aggressive, but this only happens when they’re protecting their eggs or fry from a threat.

When Can You Sex Angelfish?

Sexing Angelfish is difficult enough as it is. I wouldn’t recommend making your job even harder. My advice is— don’t even bother trying if your Angelfish aren’t fully mature. Most of the sex differences are subtle and hard to tell apart for an untrained fishkeeper.

The task becomes near impossible if we’re talking about juveniles with undeveloped bodies. For example, traits like body size, fin shape, behavior, and vent size don’t become apparent until the Angelfish reach sexual maturity, at around 6-7 months of age.

So, it’s best to wait at least six months until the fish become sexually mature and ready to breed. Then, you’ll be able to distinguish the finer differences between males and females. By this time, the fish will also start forming pairs on their own, making your job a lot easier!

Do Angelfish Change Gender?

The short answer is “no”. Freshwater Angelfish, the most popular type in the aquarium hobby, can’t change gender. Neither can most saltwater Angelfish. The fish you purchase will be either male or female from birth. However, here’s a fun fact— there’s one special saltwater Angelfish species that CAN switch genders.

This species is known as the “Rusty Angelfish” (Centropyge ferrugata). This colorful fish can switch its gender from male to female and vice-versa, depending on the selective pressures in its environment. But unless you own this rare and expensive saltwater species, don’t expect your Angelfish to switch gender anytime soon.


Angelfish are among the most difficult species to sex. Both males and females present the same obvious characteristics like dorsal fin shape, body coloring, and patterns. However, there are still some subtle differences that can help you separate the males from the females.

Body size and shape, ventral fin appearance, vent size, and behavior differ between the sexes. Males have larger, more rounded bodies and roughed ventral fins. Females have more angular bodies, smooth ventral fins, and a wider vent. But remember these characteristics only become apparent when the fish reach sexual maturity!

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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