Hi
I have a 10in oscar in a 4ft tank. with a canister filter. Can I add another oscar to the tank. We had a convict in there but we lost it to a fungus. Oacar tolerated the convict ok after they sorted out boundries.

welcome to the site jen


without even knowing the actual volume of your tank i would have to say it is too small for a pair of oscars. the best case scenerio you could have is a 4x2x2 or 120 us gallons and even though this has enough water volume the four foot length is simply inadequate for 2 large cichlids. anything smaller and you would not have the water volume and still have the length same length issue.

assuming your tank is 75 gallons or more you might be able to have a mid seized tankmate in with your oscar(something in the 6-8 inch range) and even this might be pushing your tanks capacity.

if your tank is only 55 gallons then there is realistically only room for one oscar and no tankmates.

so to make a long story short no your tank is not large enough to house to two oscars for life.

welcome to the site.

can only share ideas upon knowing the actual size of your
tank. is it 4 ft x 18 x 18 or what? what capacity of pump do
you have?

i think if you would be having a 4x2x2 tank there would be no problem in adopting 2 Os.regarding the filter may you pls specify the GPH(gallons per hr) capacity of the canister so we could really come up with the housing issues.
BTW welcome to the site were O lovers share ideas^_~

what you seem to missing is that the tank is only four feet long. if by chance you get a mated pair you will bae fine, but if you dont there will not be enough room to establish territory. reguardless of the width or depth of the tank it will only be four feet long.

im sorry if this is not what you want to hear but its better to think about it now that to have to rehome one after raising it for a year or more.