Plecostomus, also called suckermouth catfish and plecos, hail from South America. These fish eat algae and tiny crustaceans in the wild. In the home aquarium, they are prized for their propensity to eat algae, helping to keep the aquarium glass clean. However, they do need care, including feeding, beyond their algae-browsing.
Pick the Right Pleco
Hundreds of species of plecos exist, and some make better aquarium fish than others. Oddly, the common pleco (Hypostomus plecostomus), the namesake of the group, does not work well in most aquariums. Though sold as youngsters, these fish can grow to at least 2 feet long. Most people should avoid panaques (Panaques spp), also called royal plecos. These specimens can be territorial and harm other fish. However, the clown pleco (peckoltia vittata) and the bristlenose plecos (Ancistrus sp) both typically stay under 6 inches. The dwarf pleco or oto cat (Otocinclus spp) maxes out at about 2 inches, though this species should be kept in groups of at least six.
Since pleco variants vary wildly in size, so do their minimum aquarium size requirements. Otos, the smallest plecos, can thrive in an aquarium of only 10 ten gallons. However, larger species like the bristlenose need larger aquariums of at least 20 gallons. The largest species, like the common pleco, need even more room, so much room as adults that they are more suited for public aquariums or zoos. Beyond the size of the aquarium, they need dense vegetation to feel safe. Additionally, many plecos rasp on driftwood for extra nutrition, so always include drift wood in a pleco aquarium. Purchase driftwood from pet shops, since wood from other sources may contain toxins.
Many species of pleco can survive outside their ideal range, but you should make an effort to match the water conditions that plecos would see in the wild. All plecos come from the Amazon drainage, where the water is moderately acidic to slightly alkaline. Specifically, plecos prefer water with pH between 5.5 to 7.5. Make sure they have good water movement; also, keep up with water changes.
Feeding Your Pleco
While plecos will browse on algae, they do need additional feeding. You can use prepared foods from pet shops, including sinking wafers and pellets rich with algae. Plecos benefit from feedings of grocery store veggies like blanched spinach and zucchini. You can weight these buoyant foods with aquarium weights, small bands of metal you can purchase at pet shops. Plecos mostly eat veggies, but they also eat some meat. You can feed them Daphnia, mosquito larvae or chironomid larvae, also called bloodworms. Do not count on the aquarium's algae to provide all of the food these fish need.