How do you know if your Plecostomus is eating its food?

A healthy pleco with a healthy appetite is not shy about eating once they have adjusted to an aquarium. By nature they tend to be more active at night, but when food is offered during the day, they will make their way to it, even going so far as swimming upside down at the surface to suck flake food in. Some individuals can be more reclusive, especially when newly introduced.

Avoid the temptation to drop large amounts of food in at night, however, since you run a good chance of the pleco not eating it and fouling the tank. The best way to know that a pleco is eating is to observe it. If it's stomach begins to take on a sunkin shape and you don't notice any long trails of feces, then they are not eating. Try coaxing them with blanched (placed in boiling water until tender) romaine lettuce or strips of zucchini. These food items do not rot quickly and can be easily retrieved if not consumed.