If you overfeed the tank, they go like crazy! Low food stocks inhibits breeding. Just keep a good filter and nitrifying bacterial culture going.
They'll eat any fish foods (sinking, floating, omni, herbi, algae), but also go wild for dried brine shrimp or river shrimp. Not terribly fussy about temp or hardness (shells are on the thin side & will start to pit w too much GH).
They're also easy to *pop* for smaller/inexperienced turtle mouths.