I am well aware of his potential size, as telboy said i'm not a novice, i have had my frt for 5 years, he presently has an 8'' carpace, i bought him off someone who only feed him peas for the first year of his life and he had quite advanced shell curl. If this carries on the carpace will eventually crush his internal organs and he will die, a ashame for a specimen thats on the CITES list . He now eats anything i put in for him, his main diet are figs, as tey will eat these in their natural habitat, figs trees on the river bank often drop over ripe fruit into the water, also he has kiwis and i buy him soft leaved aqyuatic plants to eat. I fhe turnes into a ''fish eating monster he would be comitting suicide, too much protein will kill an frt. Although a s adults yes they will catch the occasionally fish but will seldom eat ti, mostly they wil be tasted and spat out.
Are you aware he will take 25 years to reach his full size? I guess that gives me a few years before i have to build that pond eh?
I have never bought an animal, aqautic or not without hours of research, please don't turn your dislike for parrot fish into an excuse to have a go out my other tank inhabitants, from what i have seen from you, you need to read a few books and then come back and try to give your advice. especially on the subject of compatible tankmates.