Can Common otocinclus Live With Siamese flying fox?

Both are peaceful and neither has any interest in eating the other. The issue is that they do the same job: the otocinclus is a small, slow grazer that is easily outcompeted by more vigorous ones, and the Siamese algae eater is exactly that, an active forager that reaches 16 cm and works over every rock, leaf and piece of wood in the tank.

The shared band is narrow but workable, 23 to 25 °C, with pH 6 to 7.5 for both. Hold the tank inside that window rather than at either species' extreme.

Feed as though the tank had no algae in it at all. Both species need groups, six or more otocinclus and five or more Siamese algae eaters, and a group of the larger fish alone is measured for 200 litres with strong flow and a tight lid, since they jump. Offer blanched vegetables and algae wafers in more than one place after lights out, and judge the result by the otocinclus's belly, which should stay rounded. If it does not, the tank is not growing enough for both.