i've had my 2" crocea for 3 weeks. he was very responsive and open from the start. today, home for lunch, i noticed the crocea wasn't open. now, home for dinner, he's still not open but he's also gaping and has a string of mucus across his mantle and appears to cough for lack of a better description. he's still somewhat responsive to hand movement but the cleaner shrimp is taking too much a liking to him. checked tank specs and they are fine. all other animals seem fine. i dosed 5ml of b-ionic this morning, first time since my last water change 4 days ago. i dose 1.5tsp of dt's every other day. my derasa appears fine as always. one other thing of interest is that i had several sandbed clams from ipsf and two of them surfaced and died earlier this week. what's going on?