i slowly have been putting this tank together for about four months now and it has been great untill now. a few days ago my gf bought two fish from the local pet store they didnt look healthy at all they one died within an hour and the other died the next day. we went to they pet store to see what was up we seen the other fish in the batch he died to while we were there. my water was perfect and so we got a refund on the fish not sure even what they were. but today my mudskipper which i loved died today so now im not happy at all so i found this website for some help to see what is wrong. all my fish are small babies two inches or less i have a pair of everything besides the pleco dragon and dojo there all small to. its a 55 gal banded archers angels cat sharks crabs. please help i dont want my fish to die all of them look healthy but why would the mud skipper die? i dont know if it wasnt enough land i dont know h ewas great i fed him blood worms frozen once a day he always sat on the liley pads or the turtle pad i woke up he was at the bottom of the tank not moving i picked him up and he was pretty life less so i took him to the bathroom and as i flushed him he seemed to be alive i felt so bad that i think he was sleeping or something and i killed him. the archer did shoot at him here and there but never attacked him. please let me know how to keep one thanks.