There seems to be a general grouping of small, moderately-compressed headwater-dwelling minnows as dace, strongly-compressed silvery minnows as shiners, and larger terete minnows as chubs, but this is not at all consistent, especially when you compare NA usages to European usages- the European dace is large enough to be a food fish. Some big terete minnows like fallfish and pikeminnows are sometimes called 'dace', while the tiny spring-dwelling Hemitremia is called a 'chub'.
This seems to be the kind of answer Josh was looking for. (Josh, please tell me if I'm way off on that.)
My take on some of the other posts is that lots of folks here are very intelligent and some are well-educated about fish (I don't even know what a related degree is called, sorry for the ignorance). And when you have a wealth of information to share, it can get difficult to try to summarize. I think some people on this forum could write books on subjects like this. For them to narrow it all down to a few sentences is almost painful.
Hope I don't get too much hate mail now. Just my two cents.
Edited by Jeff, 29 October 2008 - 06:49 PM.