swimming funny

Three days ago, I added a platy to my tank of one Molly fish. I've had the Molly fish for four months, but I've never seen him swim in circles. Two days ago, he started swimming in circles every few minutes (twirling). I had hopes that he was just playing around, but since he's been doing it for...

Help! One of my neon tetras is acting strange: it swims vertically frequently, its colors are less colorful that the others. I think I might of fed them a little much this morning as I was rushing a bit. He's either just stuffed himself or , I fear , neon tetra disease. Can someone please shed...