When it comes to dry fish food, there are many kinds, and they’re designed to either sink or float. Floating food is great for fish who feed at the surface, but for tropical fish that prefer their meals mid-tank or lower, it’s not going to cut it. This is where sinking food comes in.

Sinking food for tropical fish is typically in pellet form and is designed to sink either slowly or quickly as it falls to the bottom of your aquarium. Slow-sinking pellets are available in a variety of sizes and shapes, from as fine as sand to as chunky as rock salt. They are made for fish who eschew the surface and stay above the bottom, choosing, instead, to eat somewhere in-between. On the other hand, dense, nutrient-rich, fast-sinking food falls quickly to deliver dinner to your aquarium’s bottom dwellers. However, because fast-sinking pellets are so dense, you have to be careful not to overfeed your tropical fish.

Even if your aquarium is primarily populated with mid-tank feeders, it’s a good idea to add a bottom feeder, like a corycat (corydoras catfish), or two, to the mix. If your other fish miss any of the slow-sinking food and allow it to fall to the bottom of the tank, bacteria could form. A bottom-feeding fish takes care of this problem. Most importantly, always make sure that any sinking food you buy is the right kind for the fish in your tank, and always follow your favorite brand’s feeding instructions carefully.