I purchased a pair of tomato clowns and put them in my DT after their quarantined time in QT. Eating well. Everything going well and 9 hours layers , as I am watching, the clown started jerking quickly and then suddenly want stiff and still. After about 30 seconds the flow pushes the fish out and it goes head first into a hole in the rock below. I pulled him out and it floated down to the sand and did not move. I left it for 5 mins and nothing. Pulled it out. Parameters good. Any thoughts?