Key differences:
H. Goliath
Lack of prominant lateral striping.
Lack of yellow on fins. The only color on fins is red on the lower lobe of the caudal (tail) fin. The caudal fin becomes a bit more broad than on Vittatus as the fish grows, not as a juvie.
More elongated face and mouth.
Larger teeth than Vittatus of same size.
Vittatus
Prominant lateral stripes.
More colorful fins. Caudal fin has red on the lower lobe and yellow on upper. Pelvic and anal fins have yellow with white tips.
All ATFs will get the pointed sickle shaped ends on their caudal fin.