i got a lab cichlid and its in w/my brothers tank. theres 1 angelfish , 1 bala and 2 tetras. there were 2 id sharks but they were eaten. and the angelfishs fins are all nipped up. the shark has a little bite on hi 2. the tetras are fine though, not a scatch on them. do u think its the lab thats doing that to them?