Whee! Yesterday I put in 6 Cardinal Tetras and today while peering in I noticed 4 fry! They are small, smaller than a swordtail fry but visible. Just silver and black, a kind of transparent silver. I don't know if they are hitchhikers from the LFS tank, my Cardinals had fry overnight or my Danios had eggs on one of the plants and when I changed the gravel, they somehow survived. Maybe I'm a bit dim but I only noticed them today and they are a bit big now.
Maybe they aren't fish at all? I hope they aren't mosquitos. Sorry no pictures. No camera.