Trimacs where used to make OLD SCHOOL fh's years allmost decades ago, they are no longer used to make FH to the best of my knowledge. It's a HUGE step back to breed a flowerhorn with a trimac. And spots on the dorsal does not mean ZZ. There is a "myth" that all zz's with black spot on dorsal are female. IME, this is true about 50% of the time. your fish is a ZZ IMO.