I've recently gotten a juvenile moon wrasse in my 30 gal and it's been doing fine, up until around two days ago. It found itself a small crevice and has wedged itself in there. At first I thought it was stuck, but It was fine. It moves very little and buries itself in the sand lots. What has happened, and how can I help? I'll be doing some tests tomorrow before work, but hopefully it's just ammonia and I can change the water or just a phase he'll move on from. I really love him, and it would mean the world to me if anyone can anyone help me to pinpoint a cause