I've done frozen thawed fish stuffed with reptomin and hilkari turtle food, as my main diet. I occasionally caught mud minnows, chubs, and shiners from a local canal, and fed them too. I never had any issues with parasites and disease, but you cant be too careful.
As a substrate, I use to use peagravel, and river rocks, and fake plants (tried the whole amazon theme, with less maintence), it worked never had issues.
On our last batch of baby matas, I kept them simple as simple gets, bare bottom, water, and duckweed. I changed the water every few days... I feed them, mosquito fish, rosy reds, guppies, and feeder comets (when everything else wasnt available). Anything that I kept alive before feeding, was fed spirulina enriched fish food, and reptomin pellets.
Some people state the water needs to be acidic for them to thrive... I myself just used tap water, with decholrinator.... I didnt have issues.
But to each they're own....
Good luck, I'm sure you'll do fine.