Jack Dempsey and Oscar

[Rowan]

Also once they get bigger I plan on getting a 75 gallon for them, will this be big enough for them when they are full grown?

A 75 gallon tank will be big enough JUST for the Oscar and the Jack Dempsey nothing else (ideally).

This point is mute as these two fish are NOT compatible. In my case the JD was more aggressive than the Oscar and was constantly nipping at and stressing the Oscar out. The outcome was not good. Both of these fish are highly territorial.

Stick with a pair of one OR the other and a pleco for a 75G with frequent water changes, but an an even larger tank than a 75G is highly recommended.

Oscars are pigs when it comes to food consumption - they spray it everywhere.

 

[kyuubi3160]

Thought I'd update on my JD. He and the catfish were starting to compete for space too much and my firemouth was becoming the terror of my other tank, so in a last ditch effort to keep the firemouth I switched him and the catfish around.

I wasn't expecting the JD to tolerate the firemouth but I wanted to try it before I took it back to the lfs, so I watched them the whole day and to my surprise the JD basically just shooed the firemouth away if it got too close but that was it.

Its been a couple weeks now and they don't seem to mind each other at all! They will swim right next to each other and take turns using their favorite cave, I haven't seen the slightest amount of aggression after the first day. I watch for flares of aggression just in case but I'm glad I got to keep my firemouth and my JD has a friend.