Koi Angels laid eggs again. This time I took eggs. This pair has laid eggs at least 4 times. They’re in a 20 gallon tank by themselves. They always eat the eggs. Want to get fry from this pair so I put eggs in a 5 gallon tank with water and sponge filter from parents tank. With an air stone over eggs and heater too. Also put in about half a teaspoon of Meth Blue in tank. Questions are do I change tank water, if so how often? With fresh tap water or water from parents tank? Do I put more Meth Blue in tank? Thanks.