... months and they thrived in their environment. For the past three days, the majority of the goldfish have been stationary in a corner of the tank. Not near the bottom or top, but just floating stationary in the middle of the right hand side of the tank. It's like they're sleeping or hibernating. They've never done this before and I'm worried if something is wrong. It's the beginning of summer and everything I've read says they hibernate in colder months. What is going on with them? Also, I feed them twice a day, flakes in the morning and pellets in the evening. They still have a good appetite and if I walk over to the tank they will start swimming around, which is normal.