Mine eat rotting plant peices that fall of my plants...they fight my otos for them too. I have even see one of my frogs happily munching of a plant leaf that was right next to a juicy bloodworm...go figure. However they never try to eat healthy peices of plants only the rotting stuff that falls to the bottom of the tank. Sometimes they will peck at the otos weekly veggie wafer too but usually not very enthusiastically. They sure love that plant litter though. i think maybe it aids their digestion like a cat eating grass.they are obligate carnivores though so I wouldn't go out of my way to provide them with vegetables.