the eggcrate divider is the best way to go about keeping them seperated, if the female is smaller than the male cut out a hole in the divider only large enough for her to fit through. If they are a true bonded pair, that means absolutely nothing lol, the male will still beat the female. As for the fry, the male *usually* wont eat them untill they are large enought to roam free, then they are free game, but as wigglers and for a few weeks of free swimming he shouldnt bother them. besides that they will keep to the females side of the tank, i have seen in with my devils when they bred and i believe mojo has a nice picture of one of his breeders where the fry all stayed on the mothers side. A 55 gal is fine to breed a pair of devils in alot the top breeders keep th elarge adult fish in divided 55 and 75 gal tanks for breeding purposes. i save about a dozen fry and place them in a 30 gal long and then swtich them to a 55gal to grow out long enough to sex(well guess anyway) them. i have a dozen left and i still have an adult female im pretty positive about one of the fry being a male and a nother being a female so i will put them in by them selves and leave the rest didided with the mother and let them grow abit more to se eif i can get any other pairs. so more than 1 tank is nes. if yo uwant to keep the fry for a long period of time.