I just got two clownfish last night (I don't have any fish just corals). I didn't feed them anything last night, they were swimming fine this morning. When I got back from work, they looked fine, I fed them some mysis shrimp. Right after I fed them, I noticed one started swimming towards the surface, then sideways, spinning, also I saw him briefly laying flat on the powerhead, now he's disappeared in the rocks, I'm assuming he's dead somewhere but I can't find him. The other one seems to be doing fine, swimming normally, any ideas what could have happened? I'm fairly new to this and have had my share of problems with this tank. Thanks