Care
Otocinclus are some of the smallest species of suckermouth catfish and certainly the only ones likely to be seen in numbers in the average store.
Peaceful by nature, these fish tend to do best in large groups and have the added benefit of helping to control certain types of algae whilst leaving precious plant-life alone. They do, however, have a reputation for being rather delicate, so must only be considered for mature aquaria rich in algae and biofilm with a good level of oxygenation. If acclimatised carefully to such tanks these herbivores should fare well and can be expected to live upwards of 6 years. Their diminutive size means that they are one of the better choices for smaller aquaria. The tank itself should be decorated with a dark substrate, incorporating dense areas of planting and shady hidey holes amongst bogwood and rocky caves. Bright lighting will encourage abundant algal growth, which will provide some nourishment for the fish (but should not be solely relied upon). Soft-neutral conditions are recommended for Otocinclus, as are areas of moderate current. Small, peaceful tankmates such some members of the Tetra, Pencilfish and Corydoras families would be suitable. Otocinclus can be sensitive to chemical treatments and nitrogenous wastes, such as those which fuel algae outbreaks. Ensure that small partial water changes are carried out at least once or twice per week.
Shipments of fish brought in as Otocinclus affinis usually turn out to be one of a number of very similar species of Otocinclus and correctly identifying them may be tricky. Knowing their location of origin is usually important in this quest. The most frequently seen species is O. vittatus, which has a black lateral stripe that thickens into a blotch at the base of the tail. Another regularly seen species is O. macrospilus, this fish has a larger tail spot which doesn't meet the black lateral stripe and is often brought in from Peru. They might be difficult to differentiate, but the needs of all species are fundamentally identical.
May also be seen on sale as Oto or Otocinclus.
Feeding
Herbivorous. Whilst these fish will graze upon the various surfaces in the aquarium for certain types of algae and the micro-organisms it may contain, other foods must be offered on a regular basis. Algae wafers, green flakes, Spirulina tablet foods, blanched cucumber, courgette, spinach etc will all help to keep the fish in good condition. Remove any uneaten vegetable matter after 12 hours.
Breeding
These fish have successfully bred in aquaria. The trigger for well-conditioned fish is usually a cool partial water change. Small clutches of adhesive eggs are deposited onto leaves or the aquarium glass, and these should either be carefully moved to a separate hatching tank (with matching water) or all adult Otocinclus and other species removed to another tank. The eggs usually hatch after 48 hours, but this will be temperature dependent. Expect the fry to be free-swimming after a further 48-72 hours.
