Not to bash you but you should research before you buy...iv done the same thing though. I had one for a while. I didnt see it much. I fed mine nightcrawlers after lights out. Make sure its smaller than any other fish in the tank. Im sure others can give you better and more info.
they are easy to care for. just make sure you dont have any big fish that might attempt to eat it. they'll be in for a rude awakening when they get spines stuck in their throat.
they dont get that big and just get some sinking food for him.
they also like to eat at night.