giant danios

Question
i have a giant danio and he seems to never sleep as my other fish do. the question is do they sleep

Answer
Hi Christine! And thank you for your most interesting question!

~The sleeping behavior of fish is quite strange... Many times it's hard to reconize when a fish is awake or not. Of course the most obvious problem is the fact that fish have no eyelids and can't close their eyes so they appear to be awake all the time. Actually, fish usually don't go into a state of sleep that humans and some other animals do... I'm not sure if fish dream either, but it's always possible. Probably not though since fish never seem to go into the state of mind in sleep that brings on dreams in other animals.

Most fish only rest at night, some of my cichlids and the like rest on the bottom of the aquarium near a rock or plant probably either for stablility or safety concerns. My Oscar cichlid also sleeps on the bottom and sometimes even lays on his sides when lights are out. But most often, the slightest movement around his tank will make him stir. Indicating that most fish are half-asleep most of the time along with being half awake and somewhat aware to their surroundings as well. Danios are very active fish, I have a school of they seem to never stop moving. But I do reconize a state of rest in which they go in sometime after the lights go out and the aquarium is quite dark, my danios slow their movements drastically, and they often remain constantly in a certain area of the tank, flicking their fins occasionallly to remain in place...This, must be, their state of sleep. I guess this type of rest could be compared to even animals like horse and other equines, you may have once before seen a horse or a group of horses, each with one hind leg propped on it's toe and the horses' ears laid back and eyes half closed. They aren't fully asleep, but they aren't fully awake either, it's somewhere in between. Maybe like a daze, I'm not an expert on it but I think it's a good explaination.
I think danios and other small fish feel the need to be active and aware of their surroundings, they would anyway, but high on the list of prey for predators... but at the same time, they need the rest to keep going on strong and healthy.

So my conclusion to this is I am quite certain all fish, including your Giant Danio sleep. He is likely only doing so when your not around to watch him at night when lights are out.

I hope this helps!

HAPPY fishkeeping!
Karen~