I agree , the parents do all the work - but it may take a few spawns before they get it right . When the fry reach free swimming I would recommend removing the fry to another tank (bare bottom) and let them grow out there rather than move the parents , that way a smaller tank would do . I raise my green severum fry with crushed flake and "reef roids" a small grain powder food for marine inverts that is high in protein and they go crazy for it ( good feeding response ) I also crush up frozen bloodworms and they eat this as well . I have tried to hatch the eggs seperate from the parents but the hatch rate is higher when the eggs are left with the parents . If you have more than one spawn growing out in the same tank use a divivder as the older fry will eat the younger ones ( from experience ) . Good luck .
One more thing - watching the parents do thier thing raising the fry is amazing . I have trouble keeping control of my son , I can imagine 200+ LOL