smallest schooling fish

[Brown_D at pcfnotes1_wustl.edu]

What's the smallest schooling fish you know?

Some posts a while back and a trip to the Monterey Bay Aquarium a while
back have renewed my interest in designing a "fish roundabout" tank small
enough to fit in my apartment.  The public aquariums get to make large
roundabouts with tuna or anchovies, but I'd need very small fish to make
that work in a 20-30 gallon container....with a planted (of course)
"island" in the center.

Diane Brown in St. Louis, hoping the rain will slow down long enough to me
to have a dry trip home from work.