Styx is greek goddess of the underworld, no? http://www.theoi.com/Khthonios/PotamosStyx.html
That was the name of my female because of her color combo and attitude.
I think Helios is a beast of a name, I really like it.
Or Eros, and mate him!
Btw, I like how you said he wasn't a replacement of your other one. That is exactly how I felt/feel about mine.