Oscarfishlover.com

do oscars need a certain amount of sleep,it seemed like my smallest one wanted to sleep in this morning lol

Just like people, some fish need more rest than others. My oscar Dancer seems to prefer to rest for short periods and is active for hours at a time. While gidget my baby, seems to rest for hours then have brief bursts of activity. Juvenile oscars also require smaller, more frequent meals. You may see more activity if you increase the frequency of feedings.( 1-2 pellets 4-5 times a day)

Oscars are diurnal, basically these means they are active by day, unlike many catfish which are nocturnal, active at night. Most diural fish will settle down fairly quickly once the tank is in darkness, this is why it is very important not to disturb them by putting the lights on once they have settled down, this will only stress them out. It is also very important not to leave the lights on all the time, fish do need to sleep so they need to be in darkness. I don't think anyone can tell you how long a fish needs. It's like saying how long a human being needs, a lot of people can cope with less, or more sleep than other people. Obviously even with the lights out, the room may become quite lights in the morning so the fish will probably wake up anyway. I have found that if the tank is in complete darkness, the fish tend to stay less active.

I think you should leave your tank lights off completely for at least eight hours, this will give your fish a chance to sleep properly