Identify this fish, please!

[Newbie123]

Here are two pictures. I think they are the same species, but different sexes. Can you help me identify them? Thank you!

 

[aqua_chem]

Looks like two black skirt tetras, one of the long fin variety and one normal. You can't tell their genders based on that. It's just a trait that was selectively bred for.

 

[Jev12]

+1 on the black skirt tetra

 

[Goldfish loach boy]

Black skirt tetra, normal and long fin

 

[Newbie123]

Thank you, all for your quick and helpful responses. Now we know what theybare!