Can Common otocinclus Live With Royal panaque?

Neither fish threatens the other. The royal pleco is peaceful with smaller company, and at 3.3 cm an otocinclus is far below the size that provokes its territoriality toward other catfish. The problem is the menu, since both are herbivores grazing the same surfaces, and a 43 cm pleco clears a tank far faster than a small grazer can keep up with.

The shared window is 22 to 25 °C, set by the otocinclus, with pH 6.5 to 7.5 suiting both.

An otocinclus lives on soft green algae and biofilm, and a hollow or pinched belly is the sign it is not getting enough. That is the thing to check weekly here. Keep a group of six or more in a mature tank with established growth, and supplement deliberately with blanched courgette and algae wafers placed away from where the pleco sits. Bogwood is essential for the pleco, which appears to eat it and treats it as its hiding place, so put in enough that the otocinclus still has its own grazing surfaces rather than working around the larger fish.