By Iggy Tavares, Ph.D.
If the tank has healthy, mature male and female otocinclus, breeding often proceeds sometimes unnoticed in the community tank. Female otocinclus tend to be larger and stouter than the males. Courtship consists of males doing some chasing of a gravid female around the tank and is supposed to be similar in fashion to that of corydoras when it comes to egg laying.
Otocinclus females prefer to lay their eggs on plant leaves and, given the choice, where there is a water current. The eggs receive no parental care and can be eaten by other tank inhabitants. The eggs hatch in about two days, but it may take another three or four days for the fry to become free swimming.
The very small fry will attempt to feed on any algae present in the tank, which must be supplemented with crushed algae wafers and blanched spinach. To get a larger hatch, a gravid female can be removed to a separate and smaller planted tank with one or two males. Following spawning, the adults should be removed, and the fry will then have a greater chance of survival.
Triggers for spawning could include large water changes of 40 to 50 percent once a week with slightly cooler water as well as increased feeding of brine shrimp and bloodworms.