I dunno if any of you had trouble doing this, but I didn’t know and got mauled by my own hungry pet sharks before I figured it out because I forgot to hand-feed them (and pet sharks attack you if they go hungry). So here ya go.
As you probably already know, animal feeders can’t be placed underwater. This is sort of a pain, because it may seem impossible to feed sharks automatically. But the answer is actually really easy.
All you have to do is put the feeder down beforehand and THEN pour in the water and sharks.
Sharks and water already in the tank? No problem. Just group all of your sharks in one corner and build a barrier so they can’t escape. Build a barrier around the area you want the feeder to be and empty the water inside before putting in the feeder. Break the barriers, refill the tank as needed, and BAM! Automatic shark-feeder!
Note that this also works with fish.