Hello and welcome to Koko's.
Hopefully you are taking a look around the site and getting some helpful hints. In the meantime, make sure not to over feed them. GF can be quite persuasive in getting us to feed them more than they need. Veggies along with some fruits are a good varied diet. For lettuce you can tear a piece off and attach it to a veggie clip you can get from the fish store. Oranges you can chunk and throw in there (no seeds) just make sure you don't leave it in there. Only give them an hour of so to eat the orange and then remove it. It can crash your PH.
Gf love peas as well, it acts as a natural laxative for fish and will help to ward off SBD (swim bladder disease). Just thaw de shell them and cut them up and pop them in the tank.
Let us know if you have other questions, we love to help out and share our stories with fellow members.