It was from Thomas Edison, so from long ago and far from an authority on animal sleeping habits. There are a vast number and variety in species of fish, some a

It was from Thomas Edison, so from long ago and far from an authority on animal sleeping habits. There are a vast number and variety in species of fish, some appear to do the unisphere thing, some actually go dormant and rest without swimming like zebra danios, while some don't show any signs of resting like mackerel. You can't really generalize too much about the whole lot of them. Also, horses sleep.