Kinds of Catfish That Clean Aquariums

An aquarium seems a simple enough thing if you've never owned one. You buy a glass tank, fill it with water and gravel, plug in the air pump, and stock it with fish. In real life, of course, it's much more complex. Each aquarium is a tiny, self-contained ecosystem, and each fish and plant has needs that must be balanced. One common factor in most tanks is algae, which must be cleaned out regularly. Some fish species, including several catfish, will help reduce algae populations.

  1. Corydoras

    • Corydoras are one of the most popular catfish for tank-cleaning duty. Native to South America, the diminutive scavengers seldom grow beyond 4 inches in length, but they provide an effective cleanup crew. Corydoras, or Corys for short, don't eat algae. Rather, they discourage algae growth because they scavenge the leftover food, dead fish and other tank debris that would otherwise go to nourish the algae. Corys come in a wide range of vivid, jewel-like colors. They're also active during daytime, unlike most other catfish, which are mostly nocturnal. This gives them aesthetic and entertainment value, beyond their role in tank cleaning.

    Plecostomus

    • Plecostomus catfish, or Plecos as they're commonly known, are larger than Corys. In the wild they can reach 2 feet in length but seldom exceed 10 to 12 inches in an aquarium. They're best suited for tanks containing other large fish. They're algae eaters, but they're also opportunistic predators and will look upon smaller tank mates as potential snacks. They should be purchased when no smaller than 2 to 2 1/2 inches in length, because smaller specimens are too easily injured. Plecos appreciate cover, so a habitat rich in different-sized hiding places will appeal to them.

    Otocinclus

    • Otocinclus catfish are better suited to small tanks than the large Plecos, and they are not a danger to other small fish. They are slender and attractive fish, reaching a mature length of approximately 2 inches. They are social by nature and prefer to have a few companions to school with. Their native habitat is fast-moving streams, and they prefer a tank with good water movement and a lot of vegetation. Like Plecos, they appreciate a habitat with a lot of cover for them to hide in.

    Advanced Choices

    • Two other tank-cleaning species are more delicate and better suited for veteran hobbyists. Glass catfish, or kryptopterus, are uniquely fascinating in an aquarium because they are transparent. They prefer a current in the tank and live in the middle depth, where they eat food and food scraps that would otherwise sink to the bottom. They are social and travel in small schools.

      Whiptail, or twig, catfish have long, slender tails and are sedentary bottom feeders. Although not active, their odd appearance makes them a worthwhile addition to your tank. Both glass and whiptail catfish are fragile, and should not be placed with aggressive species.