In my sig you will see what fish I have in my long 20g tank, well my common pleco started climbing the back tank wall (as he always does) but this time after he climbed to the top of the tank he somehow got onto the output of my whisper power filter 40 and literally started climbing the output part of the filter even with the powerful water flowing down him. So I lifted the lid to the filter he fell back down into the tank. Why in the world would he do such a stupid and dangerous thing? He has never done this before and has never been known to be a dardevil (except the time he jumped out of the tank). So is their a way to prevent this from happening again? And is their something I should treat him with even though I can't see any damage but can't see him real good because the light is off because I just added some more fish today and don't want to stress and scare the new fish? Any help would be appriecatied.