feeding those little buggers - how much is too much?

[DiverDude]

You have to remember that in the wild, fish will eat whenever they can. Sometimes thats a couple of times a day, sometimes not for several days. herbivores nibble relentlessly.

I think being fed a reasonable amount of food, once a day, guaranteed, makes most fish plenty happy.

I suspect that your fish are cranky because they were used to getting more but will settle down when they adjust.