Order Siluriformes
Family Loricariidae
Subfamily Hypoptopomatinae
Genus Otocinclus
— Peppered Oto — Otocinclus flexilis [Cope, 1894]. Synonyms: Otocinclus flexilis, arnoldi, fimbriatus. Paraguay, Uruguay, Brazil. 4-5 cm. Olive-gray or beige with dark spots on the body and fins, belly is light. The back is dotted with small brown spots. There is a large brown spot on the caudal fin. Juveniles are darker and can be almost black. A dark triangular zone is present at the base of the dorsal fin. Males are slimmer than females.
Similar in coloration to Corydoras paleatus. Peaceful, best kept in a school of at least 4 individuals. Due to their small size and peaceful nature, tank mates should be small and peaceful. They clean plants from algae. The aquarium should be well-planted, with driftwood and shelters required. Unlike O. vittatus, these fish are easy to acclimatize and tolerate wide changes in water parameters.
Intolerant of dissolved nitrogen compounds in water. Poor water quality can be fatal. Filtration should be strong, preferably through peat, aeration and weekly water changes are required. Intolerant of high temperatures. Tall and long-leaved plants should be planted. Beneficial for a Dutch-style aquarium, where a small group provides excellent algae cleaning without harming plants.
Omnivorous species, but prefers vegetarian food, mainly green and brown algae. In addition to animal foods, chopped lettuce leaves should be provided. Part of the food should be given in the evening before turning off the lights. Sexual maturity is reached after 6 months. They live up to 4 years in the aquarium. Water temperature 23-26°C; dH 3-10°; pH 6.2-7.5.
— Otocinclus hoppei [Ribeiro, 1939]. Southeastern Brazil, Colombia, Amazon, Rio Caqueta, Mato Grosso rivers. 3-4 cm. Thin and slender body, especially in males. General color is ochre-golden or gray-brown with a golden sheen. Belly is pearly-white. A slight redness on the throat and gill covers is not a symptom of disease, but rather an indicator of good health in the fish.
A wide black stripe runs along the sides from the snout through the eye and ends before the caudal peduncle, then reappears further on the caudal peduncle, where it expands to form a large diamond- or rhombus-shaped dark spot. The dorsal fin is fan-shaped with faint black streaks. The caudal fin has variable brown and white pigmentation. Pectoral and pelvic fins are transparent. Males are slimmer than females. Similar to Otocinclus macrospilus, which has the dark spot on the caudal peduncle divided into two parts.
The aquarium should be well-planted, with driftwood and shelters required. This is a small-sized fish and therefore suitable for nano-aquariums. Sociable, peaceful fish and should be kept in a group of 4 or more. Due to their small size and peaceful nature, tank mates should be small and peaceful. Never keep them with sucker-mouth catfish, cichlids—even small and non-predatory ones—or other algae-eating species.
Lighting should be moderate, with floating plants on the water surface. Filtration should be strong, preferably through peat, aeration and weekly water changes are required. Intolerant of dissolved nitrogen compounds in water. They are also very sensitive to medications, especially those containing copper.
They clean plants from algae. Omnivorous species, but prefers vegetarian food, mainly green and brown algae, mandatory supplementation with plant matter, occasionally frozen foods and spirulina tablets. Driftwood is necessary to provide them with cellulose. pH 5.5-7.5; dH 3-14°; T 24-27°C.
— Otocinclus huaorani [Schaefer, 1997]. Amazon and Orinoco river basins. 3 cm. Females are larger and, viewed from above, fuller. Peaceful. Best kept in a group. The aquarium should be planted with live plants. Driftwood and large rounded stones are also desirable. These fish love having plenty of plants with large leaves and stones in the aquarium, from which they can graze on algae. They feed mainly on algae by scraping them from the surfaces of plants, glass, etc. Regular water changes are mandatory. pH 6.0-7.5; T 25-29°C.
— Otocinclus macrospilus [Eigenmann & Allen, 1942]. Amazon basin in Colombia, Ecuador, and Peru. Inhabit areas with lush vegetation, making them ideal fish for a planted aquarium. 3-4 cm. They have an elongated body, flattened dorsoventrally in the belly and chest areas.
The body of the catfish (except for the belly) is covered with rows of wide bony plates. On the snout, there is a pair of very small nostrils used for food searching. There are also two miniature barbels that act as sensory organs. Using these barbels, the otocinclus detects movement in the water. The mouth of the catfish consists of 4 plates, which it uses to scrape algae from rocks or aquarium walls.
This small catfish ranges from gray-green to gray-brown, with a speckled gray upper surface and a pale underside. The back is dark gray with a greenish tint. A dark stripe runs along the sides from the snout to the tail. A large triangular spot is present at the base of the caudal fin. All fins are transparent and colorless, except for dark spots on the first rays of the dorsal fin and half of the caudal fin. Males are smaller than females. Juveniles are similar in coloration to O. vestitus.
The aquarium should be well-planted, with driftwood and shelters required. Intolerant of dissolved nitrogen compounds in water. Due to their small size and peaceful nature, tank mates should be small and peaceful; they do better in a group. Never keep them with sucker-mouth catfish, cichlids—even small and non-predatory ones—or other algae-eating species. Keep in groups of 4 or more. They clean plants from algae. Plant tall and long-leaved plants such as Vallisneria.
They require soft and acidic water for care; they do poorly in hard water. They need good water quality with a high oxygen concentration. Filtration should be strong, preferably through peat, aeration and weekly water changes are required. It is very important that they are introduced into a well-established aquarium, as these otocinclus are quite sensitive to fluctuations in water parameters, as well as to the presence of ammonia and nitrites in the water.
Omnivorous species, but prefers vegetarian food, mainly green and brown algae. Their diet must be supplemented with vegetable tablets for bottom-dwelling fish and blanched vegetables (zucchini, cucumbers, lettuce, spinach, etc.). Driftwood is necessary to provide them with cellulose. Lifespan is 3-5 years. pH 6.0-7.0; dH 3-15°; T 24-26°C.
Otocinclus mariae, mura, vittatus.
Description of the genus Otocinclus, Otocinclus cocama. 
