It's like a variation of crown tail. The rays that branch off his caudal fin determines what type he is. As far as I know, there is single ray, double ray, double-double ray, cross ray, and random ray. Crown tails come in such a wide variety.
These pictures show a few variants. (NOT MY PICTURES!!) The color image is an example of a double-double ray. Basically the ray splits into two separate rays, then those rays split once more.
Random ray is not shown here, but basically it's like a randomized assortment of rays.
I looked into crown tails because I have one too. Mine is a cross ray.
Ha, tired of hearing the word "ray" yet? :D
Last edited by LittleFish2012; 11-30-2012 at 05:10 PM.