Picking out that dream fish for your aquarium is easy, it’s getting them to eat that’s the hard thing. While many fish will gobble down prepared foods (frozen shrimp, algae sheets, etc), not every fish is so eager to eat what you have to offer. That’s when you need to get creative. For fish that are natural predators of clams, e.g. certain angelfish, it would benefit you to place some gel-like food inside of a clam shell and let the fish explore and graze naturally. For fish that are natural algae grazers, perhaps attaching some algae onto a piece of rock and sticking it in the live rock structure will yield more success than an algae clip stuck the glass. This list of examples goes on and on, but the key thing to note is that your fish will probably be more accepting of prepared foods if they can eat it in a more natural fashion.