I've found a nice mixture of foods that excite the fishies and provide a wide array of stuff that's good for them. In combination with the lower pH, Les Six and the Justice League are showing much brighter colors than only a week ago. Their diet includes:

TetraMin Pro Tropical Crisps

San Francisco Bay Brand Freeze-dried Bloodworms (red mosquito larvae)

Hikari Tropical Micro Pellets for Tetras

Marineland's Bio-Blend Tropical, which drives the little nutters bananas!

I use one of the foods for two feedings per day, cycling through four days of variation. The kids love it!