Ben- Thanks, that solves that. I figured it was something along those lines, but I only know of sexing by looking at pointed anal and dorsal fins on the male. Helps a lot.
INHS has the fish listed as Misgurnus anguillicaudatus, which Google calls the Pond/Dojo/Weather loach. The only reason I knew what it was was because I've searched INHS for all the species available in my immediate area and was therefore able to recognize it immediately. They're completely legal to sell, pet stores sell them as "Dojo loach," they're quite popular, and have been in the aquarium trade for many, many years. INHS has their habitats in Illinois listed as North Shore channel (which I want to fish REALLY badly), Midlothian Creek, North Branch Chicago River, Des Plaines River, Chicago Sanitary & Ship canal, and North Creek.
One thing that kinda confuses me about INHS is that I think they're merging three rivers. The Des Plaines, the Chicago Sanitary & Ship Canal, and the I&M Canal are all separate waterways. I can't tell if INHS is merging the shipping canal with the Des Plaines and calling the I&M by the Shipping Canal's name, or if they're merging the Shipping Canal with the I&M. I would never touch the shipping canal. There are signs by the Lockport bridge warning you not to come into contact with the water. However, the I&M is fine. I would like to know which one is which, because they have listed the Shipping canal as the only place in IL to catch three spined sticklebacks, and I wouldn't mind having a pair, but I don't know which system is the right one to look in.
120 low tech native planted - Blackstriped Topminnow, Central Stoneroller, Fathead minnow, Golden Shiner, Black chin shiner, Carmine Shiner, Emerald Shiner, Sand Shiner, Spotfin Shiner, Orangethroat darter, Johnny Darter, and Banded Darter.