CichlidFish.com - Fish That Think.

Mark Stone wrote:The number of Oscars you can keep in a certain sized tank and with what tankmates is the subject of spirited debate, and always will be. There are very, very many variables in play and it's probably best for each fishkeeper to make his/her own decision based on study and experience. I keep grown Oscar pairs in 55g aquariums (well, only one aquarium now -- ) and do partial water changes approximately every 60 to 90 days. However, I recommend larger aquaria and more frequent water changes for anyone I send advice to, because experientially others don't seem to have the success I do when following my method (rather than following my advice).

Oscars have been kept in aquariums for a hundred years or longer. However, silicone aquarium sealant has only been around since the 1960s. What that means is that "large" aquariums (30g+) were, before the '60s, very exotic, rare and expensive. People that kept Oscars did so in tiny aquariums by our standards. Axelrod, in a 1950-ish book he wrote, suggests that you move your Oscars to a "large 30 gallon" aquarium when you are ready for a pair to mate! Which hints that Os were kept in small tanks when not paired off.

So, how did they keep Oscars healthy in those days? Water quality and obsessive care, certainly, but there were also tricks we learned (ha -- "we" -- I've now aged myself), using certain Oscar personality traits to lower their stress. For example, Oscars have no idea they are in an aquarium, and have no clue that they are unable to swim right out into the room. Therefore, we would try to keep lighting in the room brighter than lighting in the tank (eliminating reflection) and keeping all furniture away from the front of the tank (enlarging their "territory"), and thus lowering stress. Placement of tank decorations also plays a part, as does many other things; but the point is that for a very long time before larger (55+) tanks were available as inexpensively as they are today, Oscars were kept successfully.

Do I recommend that you keep Oscars in small tanks? Certainly not. With the aquariums/resources/equipment we have these days there's no reason to go through the gymnastics. Oscars are much easier to keep healthy and happy in larger aquariums, especially if the fishkeeper is inexperienced. But with the variables of water, filtration, feeding, noise, air quality, room size, temperature, etc. etc. I think it's best for each aquarist to study, experiment, and come up with his/her own conclusions.

--Mark