Oscars Must Have the Correct Size Aquarium
If you are planning on keeping Oscars then please consider exactly what type of fish you will be getting. You may already have an aquarium, however under no circumstances rush out and buy the first Oscar you see. Step back for one minute, take a good look at your tank and ask yourself if it is big enough to house an Oscar. If you have done your research, you will know that Oscars can get very big. Big fish require big tanks. There are two very good reasons for keeping your Oscar in a big tank. Firstly, if you house a large fish in a very small tank, you may find that you start having water quality problems. If you continue to expose your Oscar to poor water conditions than it can affect its health and even prove fatal. Also, is it fair to restrict a large fish to a very small amount of space? Personally, I absolutely hate seeing a large fish cramped up in a tiny little tank where it has no room to move, it just makes my blood boil.
You don't have to go to the extremes of getting a tank as big as the one on this page which is 300 gallons and measures 8' x 2.5' x 2.5'. However we always recommend going for the absolute largest tank you can afford and house if you intend on keeping a large Cichlid like an Oscar Fish. If I was starting over then I wouldn't go any smaller than 75 gallons if I was planning on one Oscar. However many people seem to agree that 55 gallons is about the minimum size aquarium if you want to keep one adult Oscar. If you plan on keeping two Oscars then you will be looking at a tank in excess of 100 gallons, please do not try to keep two Oscars in anything less than 100 gallons. Commercially available aquariums probably won't exceed much more than 200 gallons, so if you are planning on a very large tank with Oscars and lots of other big fish you may have to go down the route of having a custom aquarium made. In the UK that are quite a few manufacturers to build aquariums to that customer specifications.
Oscars are adorable fish, it's no wonder that people fall in love with them. However, they do require that little bit of extra attention, so please only buy one of these fish if you know you can provide it with a suitable home.