The finescale dace, on the other hand, is only found in two drainages in Wyoming and known for its scales so fine they are almost imperceptible and a dusky line running parallel across their bodies.

When a red-bellied dace and a finescale dace (freshwater fish in the carp and minnow family) mate with each other, they produce a hybrid with a very special ability: it can reproduce asexually. This ...