are bleeding hearts good schooling fish?
They're great schooling fish, I love them, but I wouldn't classify them as "active"
They move around a lot when they're young, but they turn very lazy as they grow older.
I'm assuming by "fighting fish" you mean you have a betta in there?
From your post, I'm assuming you have a school of clown loaches, a couple red tailed sharks, a firemouth, and a betta
which means the betta is eventually going to be toast. If not by the firemouth, by the sharks.
I'd get it another tank ASAP.
I have a school of buenos aires tetras in my 75, they're very active and beautiful, and stick pretty close to one another in the school. However, make sure you provide them enough space to avoid each others aggressive tendencies, they can be aggressively nippy to each other, causing a lot of torn fins. I'd also suggest getting a pretty big school of them to disperse the nipping.
They will also eat plants, so if you have a planted tank, they're not for you.
You can also try odessa barbs, I have no experience with them but I hear they're great schoolers, and the males are stunning.
That's what comes to mind for me, but there are loads of others out there. I can suggest more if you give some more info on your tank and what you're looking for.