Have you recently bought some Oscar fish for your aquarium? This is likely going to be a great choice that you’ll really love.
Oscars are such entertaining fish to own and they make for fantastic pet fish. Learn to care for them right and they can live for quite some time as well.
You might be wondering which one of your Oscars is male and which is female. If you specifically asked for a mating pair, you should have both a male and a female.
However, you might have a difficult time telling the two apart. Many people who are new to Oscars have a tough time telling the difference.
How can you determine the sex of your Oscar fish? Are there things you can look out for that will make it easy?
Continue reading to learn about the differences between male and female Oscars. This will ensure that you can tell which is which.
How to Identify Male and Female Oscar Fish
It’s very likely that you can’t tell the difference between your male and female Oscars. They pretty much look the same and that makes things rather tough.
So what are you supposed to do to tell which type of fish you have? There is a way for you to tell, but it’s best to learn about everything you can first.
Below, you’ll get information about how male and female Oscars differ as well as how they’re similar. This should allow you to understand what you need to do to sex the fish.
It can be confusing when you’re new to buying Oscars. The differences between the fish aren’t as obvious as they are with many other types of fish.
How Are They Similar or Different in Appearance?
Oscar fish are considered to be monomorphic fish. There’s a good chance you have no idea what that means, but it’s rather simple.
It’s a term that refers to fish that have the same physical appearance no matter what sex the fish is. Both male and female Oscars will look the same.
The size of the fish is going to be the same for the most part. You can’t tell which fish is the male based on size.
You’ll also find that the shape of the two fish will be the same. Both male and female Oscars have bodies with the same shape.
In other types of fish, females will sometimes have noticeable differences. This isn’t the case with Oscar fish.
You’ll also see that the fish have the same coloration. The sex of the fish doesn’t change the coloration in any way, and this means that it’s not helpful when determining the sex.
With all of this information, you’re likely confused about how to tell the difference. There is one big difference between the fish and it involves the sexual organs.
Since you have to look at the sex organs to determine the sex of the fish, it’s impossible to tell which is which by just observing the fish in the tank. You actually have to examine the fish closely to get the information you seek.
Some fish are like this and it’s not just Oscar fish that fall in the monomorphic fish category. If you’re at a store and you want to ensure that you get both a male and a female Oscar fish, it’s best to specifically ask the clerk to check the vent to give you one of each sex.
Venting Oscar Fish
The true way to tell Oscar fish apart based on sex involves venting. You need to look at the sexual organs of the fish to be able to tell which is male and which is female.
Sadly, you won’t be able to do this until the fish have reached a certain age. When Oscar fish are between twelve and fifteen months old they will be mature enough to have developed sexual organs.
At this point, you can examine the fish closely to see the sexual organs. This is not going to be easy to do without getting a very close look at the fish.
Both male and female Oscar fish have two holes near the anal area. One of the holes that you’ll see is the anus and both male and female Oscars have anal holes.
The difference between the two involves the other hole. Male Oscar fish have a sexual organ that looks like a small spike.
Female Oscar fish are different because they have a blunt sexual organ. This organ is wider and it serves as the tube where eggs are released.
Only through identifying the sex organs can you tell the difference between male and female Oscars. It isn’t easy to do, and you might not always know which is which at a glance because of this situation.
Now that you know how to tell Oscars apart based on the sex organs, you can determine the sex of the fish in your tank. It’ll allow you to confirm whether you have a male or a female fish.
It should be said that venting is not a process that is easy for beginners. Handling the fish and observing the sex organs can be stressful for the Oscars.
You might want to ask for help to determine the sex of the fish. Some might choose to reach out to an exotic veterinarian for assistance.
There may also be someone in your area who is familiar with venting Oscars. Someone with experience can help you with the process to make things go easier.
If you’ve never done this yourself and you’re not confident, it might be best not to vent the fish. Be careful and do your best to protect the health of your fish.
There is another way to determine the sex of the fish that doesn’t involve the physical appearance of the fish. You can look at the behavior of the fish instead.
Are There Behavioral Differences?
There could be behavioral differences that will help you to determine the sex of the fish. These behavioral differences aren’t always going to be prevalent.
Both Oscar fish will act the same generally. You can’t look at normal daily behavior when trying to tell male and female Oscars apart.
Instead, you’re going to look out for mating behaviors. If you believe that you have a male and a female Oscar fish in your tank, they should eventually pair up to form a mating pair.
When this occurs, you can pay attention and observe the fish. See what each of the fish does so you can tell them apart.
Males and females are going to do specific things during the mating process. If you can see what they’re doing, you should be able to tell which is the male and which is the female.
You can tell that Oscars have formed a breeding pair when they start moving around the tank together. Watch them closely and see what they do.
Put a flat rock on the bottom of the fish tank for the Oscars. Female Oscar fish like to lay their eggs on flat rocks.
It’s best to choose a flat rock that is dark in color. This makes it much easier to see the eggs since they might be harder to spot on a light-colored rock.
Before the female Oscar lays eggs, it’ll start cleaning the surface of the rock. Then it will begin swimming around in circles with the male Oscar fish.
The male should stay with the female until the eggs have been laid. The fish that lays the eggs is the female Oscar fish.
You’ll then see the male Oscar fish fertilize the eggs to make them viable. The fish will pass over the eggs and spray them.
This might be the easiest way to identify the sex of the Oscar fish in your tank. If you don’t want to use the venting method, it’d be easier to just wait and see if the fish form a breeding pair.
Note that females will lay eggs in the tank whether a male is present or not. The eggs simply won’t get fertilized if you have two females.
There are times when you’ll have a male that just isn’t interested in forming a breeding pair with the female, too. However, it’s pretty common for a male and female Oscar to form a breeding pair if they’re in the same tank.
If you can’t observe the fish doing mating behaviors, you might have to turn to venting to get the information you seek. You could just be patient and see if the two fish will eventually form a mating pair, though.
Is One Better to Own Than Another?
No, one fish isn’t better to own than another. If you want to own an Oscar fish, it’s fine to pick either a male or a female fish.
You might even want to pick both. It’s normal for people to keep multiple Oscars in the same tank.
As you learned earlier, Oscar fish don’t have substantial differences based on the sex of the fish. Both males and females look nearly identical.
They have the same coloration and they’re generally the same size. Even their bodies have the same shape.
Behavioral differences are limited to breeding behaviors, too. A female will do the things that the female fish needs to do during mating.
Other than that, the fish will be rather similar in the fish tank. There isn’t a good reason to prefer one fish over the other based on sex.
There could be reasons why you wouldn’t want to keep a female in the tank. For example, you might not want the fish to breed and you’d prefer not to have to deal with eggs.
Other than that, it’s not something where you need to pick one over the other. Both male and female Oscars will make great pet fish.
Can You Keep Male and Female Oscar Fish Together?
Yes, you can keep male and female Oscar fish together. In fact, it’s common for people to buy multiple Oscars.
You simply need to make sure that you have enough room for the fish. Remember that Oscar fish are rather large and they don’t like being forced to live in cramped fish tanks.
Buy a big enough fish tank and you can easily fit one male and one female Oscar fish. Some people even choose to keep Oscars together in small groups.
So long as there is enough room in the tank everything should be fine. It’s likely wise to put hiding spots in the tank if you want to keep a group of Oscars together.
It can be a good experience to have a breeding pair of Oscars in your fish tank. You should enjoy caring for them a lot.
You can also choose to breed the fish and care for baby Oscar fish if you want to. Some might find the prospect of doing this to be rather appealing.
It’s also good to know that you don’t have to buy multiple Oscars if you don’t want to. Oscars are actually fine living on their own.
Taking care of a solo Oscar fish isn’t going to be difficult. These fish seem to do well living in solitude, but there are people out there who think it’s wrong to keep a lone fish away from others of its kind.
It might depend on your personal stance. Just know that it’s common to keep Oscars as pairs and it’s technically fine to keep Oscars by themselves, too.
Final Thoughts
After learning the information above, you should know what you need to do. Telling the difference between male and female Oscars won’t always be easy.
These fish are the same physically except for the sex organs. They’re the same size, color, and shape.
You’ll typically need to vent the fish to determine its sex. This process is a bit difficult, and you might not want to attempt it as a beginner.
You want to do things safely for the fish. Enlist the help of someone with experience if you’re nervous.
It’s also possible to observe the mating behaviors of the fish to note which one is the female and which is the male. If you’re patient, this might be your best bet, assuming that you have a male and a female in your tank.
Jeff has always enjoyed having pets, but as a child, he was drawn to his family’s fish tank. Being able to maintain a small ecosystem and observe the behaviors and interactions in the underwater world peaked his interest early on and has kept him hooked until this day. On Avid Aquarist, Jeff shares everything he’s learned about helping aquatic life survive and thrive in a home aquarium.