I recently purchased a 10 gallon tank, and set it up, a couple days later I bought 3 zebra danios, and one of them seems to isolate itself from the incredibly active other two. He hasnt eaten as far as I've seen, and if the light is off he swims at the very top of the tank. Any suggestions as to what, if anything, is wrong with him?
-Tommy M-H
-Tommy M-H