Sleep as we know it is some thing no animal would want to do naturally , It would mean certain death. Most organisms that have developed some form of "intelligent Reaction based" survival strategy just rest with the proverbial one eye on the world.having first found a safe or secure place to rest up
Domestic animals hove developed sleep as the are in a repetitively safe environment, hibernation is for some mammals natures way of achieving a rest period coupled with a time of little or no food.
Fish in my experience tend to just go in to a stupor, But i have never seen any fish showing the sort of behavior we exhibit as sleep