I've always heard that, if a fish stops moving its fins (aka, stops swimming), its heart will stop and it will die-- with exceptions, as I've seen nurse sharks sleeping...
I've also heard that fish have no eyelids and therefore cannot sleep...
But I've seen posts here of people mentioning their favorite spots for their Bettas to rest, and I bought a resting leaf for my little guy today.
Because this is my first fish, it was a surprise to me to see Juan Pablo (my little guy) being still in the tank today. I kept poking the glass near him to make him move. I thought he was sick!
So... it's cool if he's not swimming around?
How long do they 'sleep' for? >_>
-Gabi