Fry suprise

I had a 10g I semi broke down about 2 weeks ago. It housed 99% native fish. 30 minutes ago just happen to look in it's direction and caught movement of something darting. Turn the light on and beheld 3 bluefin killifish fry. So either my dollar sunfish had spawned causing the killis to do so or the killis are not exactly obligate spawners >.> The tank has not had a filter in it nor circulation these past weeks. Go figure but a neat suprise.