Oscars are fairly tough but do have a tendency to sulk! I moved & cleaned both my tanks yesterday & Fluffy, my black Oscar is now laying on the bottom of his tank, & his colour has faded to a pale grey. Ollie, an Albino isn't as fussy but he is sitting in his corner & wont come & "talk" to me, lmao. Great characters, eat just about anything ( including any careless fingers!) & apparently can be trained to jump through hoops if you have a large enough tank. I haven't tried that but Ollie will jump out of the water for a block. I have my tank set at 28 C & use small gravel due to the them throwing the larger rocks around, as Miley said, they do throw the rocks quite hard & breakage is a real risk! Miley, how did you get the ping pong balls submerged? I'd love to try that with mine!