Yes my sea hare was stuck in powerhead, still alive and trying to free himself. first unpluged powerhead, removed from tank to a bowl of water from tank to keep him submerged and safe from possible contamination to tank. Removed pwerhead bottom to see if it had got into propeller, just stuck thru the vents in 3 places, carefully bent away each segment of vent opening on pwerhead carefull not to injure sea hare. Freed one peice at a time. Poor fellow had large bubble type swollen, light blue-green sores about the face area, after overnight in a sick tank(2 1/2 gals) sores went down in size and he appears to be eating and moving fine. I returned him to tank, and 48hrs later it is fine. I may point out , luckily the skin was never broke. I suggest, keeping glass around powerheads and filters free of any algea as not to attract sea hare to graze in that location, also I tied peice of nylon stocking around powehead so waterflow can still pass but any animals can not get close. I am converting to sump instead of filter.