Can't figure it out! Is it a delta?
OH and I snapped a pic of this at my local PetCo:
The funniest part is all of the cups labeled "Halfmoon" are actually Delta Tails and all of the cups labeled "Delta Tail" are actually Double Tails!
And it's like that at EVERY PetCo I go to! Not to mention, the picture of the Halfmoon on the cup label looks NOTHING like the "Halfmoon" they have displayed on the sign there :]