Order Siluriformes
Family Loricariidae
Subfamily Ancistrinae
Genus Ancistrus
Distributed in the northern and central parts of South America from Panama to Argentina. The genus includes armored catfishes inhabiting fast-flowing and rocky mountain streams in the Amazon basin and in Guyana. Their typical feature is elongated lips with horn-like suckers on the underside, a flattened body, and a hard and sharp first ray of the pectoral fins. They have a mouth with elongated lips shaped like a sucker, the edges of which are covered with horny plates that allow them to scrape algae off aquarium walls, plants, and driftwood.
Male – Female
Males differ from females by the presence of “horns” on the head; in adult males, these are “branched”: the outgrowth divides into two, and each of these, in turn, also divides. Sometimes females older than two years also have growths, but they do not branch and, as a rule, their number does not exceed four. The outgrowths on the heads of females are always located in a single line on the very edge of the head, while in males they grow in several rows. If your Ancistrus are not yet a year old, the females’ heads will be smooth and the males will have slight “bristles”; if your catfish are over two years old, the males will have magnificent horns, while the females’ heads will either be smooth or have a single row of horns.
Aquarists have bred various color morphs – albinos or yellow Ancistrus, which have a white or yellowish base color with red eyes, and often faint red spots on the body. Ancistrus with a rusty-red body color and black eyes have also been created. Veiltail forms with elongated fins, including albino forms, exist as well. Interesting species exist in nature: — Ancistrus cryptophthalmus. 8 cm. Originates from an underwater cave in Rio San Vicente in Brazil. They live deep in underground caves, lack pigmentation (almost entirely pink) and eyes. Juveniles are born with eyes, but they disappear after some time (covered by a layer of skin). They have more teeth than ordinary fish, which indicates that they feed not only on algae.
In the aquarium, they like to stay in current zones created by powerheads or filters. It should be remembered that they can crawl into filters and water outlet tubes, which can lead to the death of the fish. Towards other fish that are not food competitors, they are peaceful; however, males often fight among themselves, especially when food and living space are scarce. It is advisable to keep no more than one adult male per 100-liter aquarium – these peaceful and herbivorous fish can fight to the death over females. If it is impossible to separate them, you should consider creating a larger number of hiding places in the aquarium.
There must be only one sexually mature male! In his behavior, sexual motivation is paramount rather than feeding motivation. Male Ancistrus are larger than females. Apparently, in nature, they guard a large territory along with all the females within it. The male must be large to successfully resist another male. And he only attacks males. He does not touch females or young fish. Having patrolled his territory, the male Ancistrus hides in his burrow, where females ready for spawning swim by themselves and, sitting around, wait for him to deign to let them into his apartments. One male can spawn with multiple females. The aggressiveness of male Ancistrus towards each other during the spawning period is especially high.
Nocturnal fish, they become active at dusk and during the day when atmospheric pressure drops. They love clean, oxygen-rich water. Aeration, filtration, and water changes are mandatory. Plant matter, especially at a young age, should make up at least 60% of their diet. This can include filamentous algae covering plants, the bottom, and aquarium glass, meaning the fish act as cleaners. One pair is enough to clean a 100-liter aquarium. Vegetation and driftwood are required to provide ballast and cellulose, which are necessary for digestion. With age, they scrape algae less effectively, especially when overfed with live food.
They reach maturity at 1-1.5 years. The spawning cave should be more than twice as long as the fish, and no wider or higher than the size of the fish with spread fins, and should also have only one entrance. The narrower the cavity, the safer the fish will feel. They live for 5-8 years in an aquarium. Most Ancistrus tolerate hardness up to 30° (optimal 2-15°), pH 6.5-8.2 (6.5-7.5), and temperatures from 20 to 28°C (22-24°C).
Identification: Genus Ancistrus
— Ancistrus bolivianus [Steindachner, 1915]. Synonym: Xenocara boliviana. Bolivia. 9 cm. Vegetation and mandatory driftwood are needed to obtain ballast and cellulose, necessary for digestion. With age, they scrape algae less effectively, especially when overfed with live food. These are nocturnal fish; they become active at dusk and during the day when atmospheric pressure drops. Aeration, filtration, and water changes (at least one-third of the volume weekly) are mandatory.
Ancistrus cirrhosus, claro, dolichopterus.
Acanthicus adonis, Acanthicus hystrix. 
