My pleco keeps swimming frantically to the top of the tank (65 gallon) Then floating to the bottom on his back.
Answers (1)
My best guess would be that he doesn't like the other fish in the tank (if there are any), or he doesn't like the tank. I suggest you test the water to make sure that there's nothing in it making him not want to be in there, and also change the water and clean the tank, just in case. Pleco's have been known to act strange like that.