Complex sentence: The blackfish should not be kept with crabs and mollusks, as its appearence suggests, while other fish, like oyster cracker toadfish, will do fine with anything that isn't a fish small enough to fit in its mouth.
Split into simpler sentences: The blackfish should not be kept with crabs and mollusks, as its appearence suggests. While other fish, like Oyster Cracker toadfish, will do fine with anything that isn't a fish small enough to fit in its mouth.