Mixed tetras?

[Leah]

Yup from my freshwater day's id say it is a no no. It would be better to keep cardinals with
neon's and glowlight's more of the mild mannered schooling ones. Had my troubles mixing them as well.

[shrimpchips]

The serpaes should be fine with cardinals/neons. The bloodfin will, as you have found, rip the shat out of the little ones.

I've found that most of the deep bodied tetras are relentless fin nippers/fish killers. I once had a single large Rio tetra that killed everything else in a 20g.

[Leah]

Maybe that is how it got the name blood fin.