ADFs are tough little critters and can survive in most conditions (even unheated and unfiltered at room temperature and with a regular water change). They do not harm fish. Most fish will out-feed the frogs (which are slow, stupid and have poor eyesight) so frogs must be fed directly if they are to thrive in a community tank. Defrosted bloodworms in a baster or pipette right infront of their nose is best, especially if you have bottom feeding fish. They like places to hide, and dislike deep tanks (since they must come up for air). ADFs are great, just make sure you are not mis-sold ACFs instead.