Bottom feeders are aquatic animals who feed on or near the bottom of a body of water (i.e. the seafloor). They are also known as demersal fish or ground fish. Included in this category are cod, flatfish (halibut and flounder to name a few), haddock, bass, and a few species of shark and catfish. Also, shellfish, crayfish, crabs, sea anemones, starfish, snails, sea worms, and sea cucumbers are bottom feeders.
A lot of concern about whether a fish is a bottom feeder or not stem from dietary concerns often related to religion. The belief that the consumption of bottom feeding fish is wrong comes from the idea that because they eat and clean things from the floor of their environments, including algae and uneaten remnants of food left from other organisms, they are unclean and therefore unfit to eat. However, the consumption of bottom feeders has been proven to be more sustainable in terms of the consumption of seafood because these animals are at the bottom of the food chain and tend to reproduce most quickly.
Because of this many are sought as pets, as they can help keep in-home aquariums quite clean while filling out their natural roles. However, it is important that when looking to purchase a bottom-feeding fish for your aquarium that you make sure first that the tank can sustain them. If your tank is very new chances are it hasn’t had the time to produce enough algae and food for your bottom feeders. If you place a bottom feeder in a tank that does not have a lot to feed off of your fish can starve and die.
You can also supplement the diets of your bottom feeders in order to keep them fed and healthy by purchasing items such as algae pellets and pleco wafers.