How much and how often should I be feeding 4 Zebra Danios, 2 Dwarf Coral Platies and 2 Black mollies? I am using flake food and have been giving a small pinch morning and evening as advised by LFS but I think this may be a little too much. However, all the fish seem hungry all the time ad rush over as soon as anyone is by the tank - is this just normal greediness?