I've never seen one but I looked it up. Etheostoma caeruleum is the scientific name , they are native to north America. They live in fast moving streams and small rivers and the best part is they only live in pollution free water. So wherever you saw this little guy is a clean water source.
I don't think so, they are native, and there were lots of them all the same size. Hard to photograph, I guess they didn't call them "darters" for no reason.
Yes, I've seen one in the wild before. It was many years ago on the South Fork of Wildcat Creek in Tippecanoe County. They are pretty small, just a few inches long. I actually scooped it up in my hand for a closer look, then set him loose.
That was cool, i have fished indiana waters for 40 years and never seen one of those. But years ago in a small creek while fishing with mmy grandfather, he caught a rainbow trout. It had a tag of some sort on it and her released it. I was just a kid and thought we should keep it. buts gramps said no that some day it would not be so rare. But other than lake michigan I have never caught or seen one caught in indiana. By the way this was near seymore.