i think that once you are done growing the them out it should be fed once or twice every couple months at the most. The reason is because they can't digest mammalian foods as well as aquatic foods so over time all the minerals that weren't/couldn't be digested start to build up and cause other problems like blockages. IMO though its something that should be used as a treat, grow-out, or (what i use/used it for) if a poly won't eat feed it that. So if your poly is on a hunger strike and you're starting to push the month+ mark then i'd feed beefheart and then the poly will start to like that (at least mine did). Then start stuffing the beefheart with the pellets or whatever you are wanting it to start eating. Then when they start to except that try and rub the beefheart (so when they taste it it tasted like beefheart) on the pellets (or whatever you want to feed it) so they start to except them. May not work for you, but it definitely worked for me.
