Sorry all, definitely not a barb, certainly not a Roseline Shark (Puntius Denisonii).
Looks like a Least Killifish. Female most likely. It seems to be a little scared as the coloration isn't truly there. Great find though! They are lovely little US native fish. The males used to be the smallest known vertebrates! If you can find some more k
would get some! They can be kept in small unheated bowls. Again, great find!