Ive had him for about 6 months real mean fish even attacks the pleco from time to time but I can't seem id him properly he's not a small fish by anymeans (about 23")
It's most likely stressed from being in too small of a tank and with too much lighting. You can try adding floating plants (plastic or real) to diffuse the lighting. This fish needs a larger tank sooner than later.
I would expect it to grow at least another foot.
Read post #5 for more info.