I once came back from a vacation late at night to see all of my cichlids lying on the ground. I assumed they were dying and was in full panic mode, but it was too late at night for me to do anything.What happened was I dropped food in, and the next morning (today), he was just sitting in the same place food not eaten. I poked him with a Turkey Baster, and he was off. He ate. May have been sleeping.
It wasn’t until morning that I realized they were sleeping.

Fish like to scare us.