The life span of Oscar fish are generally 10 – 13 years.

DO NOT attempt under any circumstances to keep an Oscar fish of any size in such a small aquarium
Photo provided by Flickr
Predatory fish always swallow their prey headfirst in order ensure all the fins are folded back and don't catch in the throat. When an Oscar decides it fancies catfish for dinner it will often take the catfish in its mouth and try and swallow it. When it realises that it's not going to be able to do this it tries to expel it. This is when problems arise. A lot of catfish have got spikes built into their fins. These spikes are extremely sharp as a lot of fishermen have found out. What happens is the spikes dig into the Oscars throat or mouth and the Oscar cannot spit the catfish out. Over the years, we've probably had about five cases of this exact thing happening. If my memory serves me well, at least one Oscar actually died because the person couldn't get the catfish out in time. The other cases involved the Oscars owner having to manually remove the fish from the tank and use tweezers to get the catfish out of the mouth of the Oscar. So really what I'm trying to get across is that even though catfish are a good tank mate, small catfish like Pictus species that don't grow much more than 6 inches could be a problem if purchased when very small.
Tiger Oscar fish - this most resembles the original Wild Oscar fish and is extremely common
Photo provided by Flickr
Longevity: Oscars can live for well over a decade. Success with these fish is measured in years, not months. These fish are a long term commitment that should not be taken lightly. I spoil my SGT and Tiger Oscar more then my other fish cuz I love them.
Photo provided by FlickrOscar fish belongs to cichlid family and are known by scientific name Astronotus ocellatus.
Photo provided by FlickrOscar Fish Life Expectancy: 13 years
Photo provided by Flickr
There are really only two known ways of successfully telling apart a male from female Oscar fish. The first involves a process called "venting". Somebody who knows what to look for will be able to examine the genitals of the Oscar fish. By comparing the shape and size of the opening will determine the sex. The second and absolute 100% guaranteed way of sexing an Oscar is when you see the female laying eggs and then the male fertilising them.If you are lucky enough to witness Oscars laying eggs then you may want to take a little peek at the underneath of both fish. You will then see the difference between the female and male genitals. The female's genital papilla is what most of us refer to as an egg tube. It's fairly wide at the end and whitish in colour and sticks out quite far. When she's not laying eggs it retracts completely inside her. The male's genital papilla is very different from the females as he only has a small spike from which sperm is deposited from.I have written a more in-depth article on how it is possible to .This is actually a task that is easier said than done. In the Cichlid fish world, the female will normally choose a partner to pair up with and breed. Therefore it's not just a case of buying two Oscars and waiting for them to breed. You might get lucky and end up with a breeding pair, however, the chances are you've either bought two females, two males or a pair of Oscars that just aren't interested in breeding with each other. In order to increase the chances of finding a breeding pair, you will need to get several Oscars and keep them together in the same tank for a few months. What you hope will happen is two of the Oscars will eventually break off and form a pair together.If you are lucky enough to witness Oscars laying eggs then you may want to take a little peek at the underneath of both fish. You will then see the difference between the female and male genitals. The female's genital papilla is what most of us refer to as an egg tube. It's fairly wide at the end and whitish in colour and sticks out quite far. When she's not laying eggs it retracts completely inside her. The male's genital papilla is very different from the females as he only has a small spike from which sperm is deposited from.There are really only two known ways of successfully telling apart a male from female Oscar fish. The first involves a process called "venting". Somebody who knows what to look for will be able to examine the genitals of the Oscar fish. By comparing the shape and size of the opening will determine the sex. The second and absolute 100% guaranteed way of sexing an Oscar is when you see the female laying eggs and then the male fertilising them.Before rushing out to buy your first Oscar take some time to look at what is involved in keeping one of these fish. Surprisingly, Oscars can live for over 10 years, that's the same as a pet dog. So it's important that you understand that getting an Oscar is a long-term commitment to looking after your fish's welfare. Your Oscar is going to rely solely on you to make sure that it's home is clean and safe at all times. Your commitment to your Oscar will mean carrying out tank maintenance at least once a week for the entirety of your fish's life. Changing water and cleaning substrate shouldn't take more than one hour every week, but it will be a task that cannot be overlooked or ignored.