How can you tell if an Oscar fish is a male or female?

Question

I have an Oscar fish that is about 2 years old and about a foot long if not longer. I was just wondering how to tell if it was a male or a female. thanks in advance. ~angel eyes~

Answer 1

This says it best:

Determining Oscar Gender
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The popular answer in a discussion about sexing Oscars is that it simply cannot be done other than through dissection or observing mating. However, Oscars are rather easily sexed under certain circumstances, and experienced Oscar keepers can usually determine the correct gender at a glance.
An absolutely certain sexing method is by venting, or looking at the fish's vents and comparing their size and certain other characteristics. I usually don't recommend this, because the fish needs to be removed from the aquarium and held in such a manner that the vent can be observed. Anyone who has ever tried this, and has their hands cut to pieces by the extremely sharp 2nd Dorsal, and their clothes drenched by stinky aquarium water, and their fish flopping about on the floor (because it is impossible for even Hulk Hogan to hold an Oscar still!), will agree that no one needs to know the sex of an Oscar THAT bad. But, there are certainly other ways to tell genders without such dramatics.
Oscars follow general Cichlid and aquaria guidelines as far as sexual differences. In nature, and, as a matter of fact, in nearly every species except Man, males have a tendency to be more colorful and larger. The male lion has more hair; the male Betta Splendens and the fabulous little Millions Fish have huge fins; you get the picture. This natural tendency is no different for Oscars, except that the differences are much more subtle and need an experienced eye.

If certain conditions exist, sexing Oscars is a cruise. If you are certain your fish are the same age, have been fed similar diets, have approximately the same disease history, and have been kept in similar water conditions, then basic Cichlid sexing guidelines always apply. These are that the male is longer and not as compressed as the female, and has a body shape closer to the traditional Cichlid form. He has a more defined forehead, rather than the round female forehead. His fins are larger, and the tip of the 2nd Dorsal fin is a point, rather than the female's subtle rounded tip. In the wild, many males have a number of eyespots that extend from the traditional caudal peduncle spot up and forward under the dorsal fins. This, however, has never been observed in aquarium-bred males. Males also have a tendency to be more brightly colored, especially in the regions that do not change pigment with mood: for example, the circles that surround the eyespots.

Note that if Oscars are raised in dissimilar circumstances, the opposite may be true. If you put a female who has been raised in ideal conditions together with a male that has been underfed and mistreated, she will be larger, more colorful, have longer, flowing fins, etc. The only real clue is body and forehead shape, and an aquarist should not trust those observations until he has owned his hundredth Oscar!

Dominance and/or aggressiveness is not a good indicator of gender. Oscars can be aggressive or not based on any one of a hundred things, from noise level in the room to size and decorations in their aquarium. There are just too many variables to make an educated gender decision based on aggressiveness.

Using these guidelines, it is very difficult to sex juvenile stock at LFSs, because we don't know their age and history. There are some hints in body shape when they are an inch or larger, but it takes a lot of experience to tell. The most usual method of finding a mating pair should be followed, rather than trying to determine gender at an LFS: and that is to get 6 or 8 juveniles, trust the laws of chance that you've gotten both males and females, and wait until a mating pair forms.

Answer 2

Female Oscar Fish

Answer 3

This Site Might Help You.

RE:
How can you tell if an Oscar fish is a male or female?
I have an Oscar fish that is about 2 years old and about a foot long if not longer. I was just wondering how to tell if it was a male or a female. thanks in advance. ~angel eyes~

Answer 4

most female larger cichlids are fatter of course. I dont believe i know really external differences, The best way to breed them though is to get a group and allow them to pair up. Mike most cichlids, they will form bonded pairs.

for more help please see my fish forum: http://fishroom.rapidboards.com

Answer 5

This site explains it pretty good, and it looks like you can't tell it unless you hat 2 of them
http://www.oscarfishlover.com/index.php?option=com_content&task=view&id=32&Itemid=78


Hope that helps


Good luck


EB