Not every fish from Halfmoon Betta parents will get a tail spread of 180 degrees.

Some Bettas almost get there aznd stop. These offspring are called Super Deltas.

Wide tails that do not get close to the Half Moon or 180 spread are just called Deltas.

These fins are different in shape to the traditional veiltail as they do not have the arch and droop of the veiltail.

They are branched and shaped like the halfmoons and just fall short of the branching needed to make that 180 degree spread.