I think hikari has a fast growth formula. My fish prefer hikari over nls. They even go as far as picking out the hikari pellets. You shouldn't rush your fish's growth too much. Just do big water changes like someone else had mentioned and you could try live foods if your fish are big enough but don't use feeders. Try small guppies or danios because they will be kept in better condition than rosie reds or goldfish plus goldfish are fatty which isn't good. Another idea would be to make your own food that's specifically geared towards that species of fish
Sent from my N860 using MonsterAquariaNetwork App
Sent from my N860 using MonsterAquariaNetwork App