Cories--what ARE they eating?

[hellocatfish]

My daughter was watching the cories make their rounds over the plants and asked me if they were eating the plants. I said no, but I couldn't answer her followup question of exactly what, if anything, they are in fact eating. They are just going over the plants plus all decor very thoroughly with their mouths.

Are they eating anything, or are they just searching? I can't see anything, not even algae, that they could eat on these surfaces, so I can't understand their intensity and diligence and even what seems like enthusiasm for going over the same surfaces over and over. Thanks for any help. Leave it to a kid to get me looking up stuff I kind of took for granted that I knew, or just never really thought about.

[Marc van Arc]

Are they eating anything, or are they just searching?

Hello HC,
Tell your daughter it's a combination of searching and eating. They skim the surfaces in order to find things to eat
(and it's much easier for us to see them eat flakes than it is to see them take microscopic food particles) and when they've found something they'll simply eat it.

[hellocatfish]

Ahh, thanks so much! I'll tell her. I think I'll have to be purchasing a microscope sooner rather than later so I can show her there's a whole tiny almost invisible world going on that the fish interact with constantly.