I have two oto cats in my 20 gallon tank. For about a week or two, they didn't really do any cleaning of my serious brown algae problem, but since then they've done a fairly good job on the fake rocks, fake plants, and even the substrate. However, they don't seem to be cleaning the tank glass? I see it slowly building up and getting worse, at least along the back of the tank, and on the sides. I don't remember if the front has the same issue. The area right at the substrate/glass is the worst, where it's almost solid brown algae. I should also maybe point out that the back of the tank has one of those fake backgrounds, but I don't think that really makes a difference.
Are they just not finding it, or maybe just prefer having their mouths pointed flat as opposed to vertically up/down? They used to attach to the glass vertically up a lot more often, but now seem to mostly keep their bodies flat. It's not an issue for me to manually clean the glass, I just want to know if they might eventually feed on it, in which case I'll leave it for them. It's been at least two weeks since they've finished mostly cleaning the rest of the tank. Throughout the whole cleaning process, I've been feeding them 2-3 shrimp pellets once/day, so it's not that they've found something else they like more and aren't eating anything else.
Are they just not finding it, or maybe just prefer having their mouths pointed flat as opposed to vertically up/down? They used to attach to the glass vertically up a lot more often, but now seem to mostly keep their bodies flat. It's not an issue for me to manually clean the glass, I just want to know if they might eventually feed on it, in which case I'll leave it for them. It's been at least two weeks since they've finished mostly cleaning the rest of the tank. Throughout the whole cleaning process, I've been feeding them 2-3 shrimp pellets once/day, so it's not that they've found something else they like more and aren't eating anything else.