Mine books and film for your favourite character names! My bettas are Delirium (from Sandman) and Sigmund (as in Freud). In the past I've had Shelmerdine, Bonthrop and Orlando...
How about "Bubblegum King"? Nah, just joking. He's a lovely boy, but he'd be easier to name if he was female!
In all seriousness...
Jack (After Captain Jack Harkness, of Doctor Who/Torchwood infamy! He wouldn't be afraid to wear pink...)
Eclipse (Doesn't the moon look pink/red during some sort of eclipse?)
Harvey (Same thing as with Eclipse- doesn't the moon look pink during the Harvest moon each year? Or am I way off base?)
If he were my betta, I think I'd call him Samuel... Don't know why. It just suits him, and I have a thing for giving my bettas names that start with S.