引用一段關於冠尾定義的英文:
Crowntail (CT) bettas are very similar to combtail bettas,
where the rays of all fins grow beyond the webbing of the fins like a fringe.
The difference between CTs and combtails are that CTs have extended rays far longer than those of a combtail betta.
A good proportion would be the rays being twice as long as the webbing of the fins.
Good CTs should have strong and thick rays,
such that when the fish is flaring, all the rays stand up firm.
Variations of CTs are: double ray (dr) CTs,
double double ray (ddr) CTs, and king CTs.
(source : Chris Yew, Sg)