Here at work, I had a tank that was full of blackbanded darters (about 10), 2 tessellated darters, 1 dollar sunfish, and 1 juvi spotted sunfish. Recently all fish were moved out of the backup tank and onto exhibit. 4 Days after the fish move a water change was done on the backup tank and it was noted that there were 20+ fry swimming around the tank. All were in the water column and more towards the surface. Is this behavior of darter fry? Unless the two sunfish hybridized, the only thing they could possibly be would be darters (likely blackbanded). I've never hatched darters before, so I'm unaware of if they would swim in the water column as fry and then later move to the bottom of the tank. Another reason I suspect darter fry rather than hybrid sunfish fry is they are extremely elongated fry, much more so than any sunfish fry I've ever seen.
If anyone has any info, I'd appreciate it. There doesn't seem to be much out there on blackbanded darter fry.