Plecs will eat a variety of green foods. If all else fails, you can buy special plec "algae wafers" and this will do an admirable job. I like the Hikari brand, but there are others.
My Panaque loves cucumber rind and sliced courgette (zucchini). Never shown much interest in peas. Bogwood is important, too. They use it as fibre in most cases, and as actual food in others, but all plecs benefit from having some in the tank. Even a little fragment will help.
Some plec species need a bit of meat in their diet, such as bloodworms or a small chunk of fish meat or prawn. Try and identify your plec species if you can, and then once you know that, you can choose a diet tailor-made for that species. The Loricariid catfish subforum is the place to go if you need help identifying your fish.
In theory, plecs are most active at night. But when settled in they will be day active, providing the room is quiet. They are often quite skittish.
Cheers,
Neale
