Hello! I have a tank set up. Water parameters are good and I have 7 glo fish danios, 2 gouramis, and some ghost shrimp. When I first put in three of the danios they stayed on the bottom breathing heavy. It was only them and one gourami. Their tail fins were clamped and it looked like their jaws were vibrating. The next day one had died, one was swimming at the top (jaw still opening and closing quickly) and the other was sitting at the bottom shimmying and jaw vibrating. I added a few more glo fish to help with the stress. now everyone is happy but the one on the bottom. He is still down there in one spot shimmying, not eating, and his mouth is partially open no longer vibrating. I really don't know what it could be since everyone else is fine. Even the one showing the same symptoms is shoaling with the new ones. I have a heater, thermometer, air pump and filter all in the take. I got my water checked at my LFS and they said everything was fine. I really don't know how to help the little guy. He also looks fine. No spots, no frothy mouth, just clamped tail fins. Any ideas? Thanks!