Iv had my 2 for a week and i now what you mean there cool little predators there great to watch. I sit there for hours and give my housemates running commentary on thier every move
Today i fed them fish for the first time. I only bought 2, 1 each. (there only an occasional treat until i breed my own).
The first one was funny. He was so scared that he actually managed to jump out of the tank to get away from Tiger and landed on the glass top. I nudged him back in and Tiger swallowed him hole as soon as he hit the waters surface
The other one seemed to fast for Rocky, my still unfed O. He managed to hide and dodge for about 20 minutes. Just as i was telling my housemate that this ones fast it might end up living in the tank for good, i looked back over at the tank and its tail was hanging out Rocky's mouth Lol !
good times