You are correct. The bluntnose is much better at surviving predation compared to fatheads. Although with inadequate refuge areas smallies will eliminate the bluntnose. An abundant population of yellow perch in a pond with minimal habitat - refugia will eliminate the bluntnose. Bluntnose are able to maintain good densities and thrive in many natural lakes with bass, walleye, pike and yellow perch, however in these waters there are always weed beds, good amounts of emergent vegetation and often rocky &/or woody cover. You can't expect quail and pheasants to live in open fields with predators around without good, adequate, diverse cover. The cover density would depend on how many predators there are preset per unit area.
The banded killifish gets to a decent size maybe 5". I have no experience with them and do not use them for fear they will compete and eliminate my blackstripe topminnows.
http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=685There is a western banded killifish
http://aquafind.com/Killifish/Killifish-Western-Banded.phpI think topminnows and killifish would use the same niche. It appears banded killifish occur in Ohio and the upper midwest, but I would try them in a perch - smallie pond or a perch pond if did not have my topminnows. I think the banded killifish would be better at avoiding predation compared to any of the topminnows mainly because the killifish get larger than the topminnows.
