So I've had my 140 gallon tank for about a year and a half. Doing well. I had a friend breaking down his tank put a harlequin in my tank. I'm constantly tinkering with my tank and would find maybe 1 or 2 asterina a month and remove them. The morning after I put the harlequin in I removed atleast 60 asterina from the tank that surfaced. They were everywhere. Did they sense predator and run for the hills?? This is very weird. Anybody have any insight?

