no need to pm me. i noticed the thread.
he is not a double tail, though his large dorsal fin suggests the possibility of him being a het for it.
i do not say any 'extra fins'. are you reffering to the rays that are curled to one side of the fish? that is just ray curling, its not harmful and just happens. its not genetic but rather environmental, though people arent sure what causes it. some say hard water, others say temperature. its rarely seen in non-crowntails, because if rays curl, the direction is pretty random, so if one tries to curl left, and its neighbor tries to curl right, the webbing connecting them pulls them both right back. but crowntails lack this webbing and so they are much more prone to curling.
here is a curled CT: http://lh4.ggpht.com/_-3FxoS1UsOE/TB...0/P1080538.JPG
see the fishhooks on the rays? thats ray curling. i had one CT who developed corkscrews on some of his rays, however for the first 3 months, his rays were perfect; it developed over time. each curled ray is a fault in the IBC shows, but its not hereditary.