Head and Tail Light Tetra

[Clear_View]

I just bought two head and tail light tetra today, and I got them home and looked them both over, and they are both happy and healthy fish. I just had one question though. They both look pretty much the same except one has a little bright yellow going across some of its fins. It doesn't look like a disease or anything, just like natural color on its fins. Do you think this is a different type of tetra, or do some head and tail light tetra have this on them? Thanks for any help.

 

[Dwarfs]

I don't know about the fins, they sound ok. The only advice I can give is to go back and buy 4 more so they are happy with their little school