The rainbow experiment didn't end so well. I got a huge rainbow, over 4 inches and fat. The jaguar seemed very interested in it at the begining, and followed it around the tank for a while. No attacks though. Surprisingly it was the gars that got the rainbow. I kept them well fed for 3 days, and the rainbow did fine with only some fins bitten. Then I had to go away for another 3 and when I got back home I found the rainbow dead floating on the surface. My gars couldn't eat it but bit it to death. I'm going for bala sharks now. Fingers crossed.