whichever one i feel a connection to. i don't base what i buy, on tail type, but how well i connect with them. when i got ichi, i had the choice of so many different bettas, but i kept coming back to him. i didn't know he was a delta, until i got home. even when i had the choice of a beautiful marble possible dragon halfmoon, or the plain, boring white HMPK, i chose the HMPK. who was the same price as the HM. but, i bonded with Theo.