My guppy fry are in my 4 gallon breeder tank. i have been feeding them finely crushed flakes but i want to know how to give them egg yolk i dont get that. By egg yolk does that mean you boil and egg and open the egg to the core and take out that boiled egg yolk and drop it in the tank? or is it something else? They dont sell brine shrimp eggs at my local petsmart i dont know what else to give them besides the crushed flakes help?