Yes, they are different fish. VERY similiar but different. Many of the notable differences are in the teeth structure which doesn't help much when trying to compare live fish but there are a few other things you can use for comparision:
Otopharynx tetrastigma females have much smaller black blotches then female Tramitichromis intermedius.
O. tetrastigma have a longer face/mouth then T. intermedius which has amore rounded head.
T. intermedius are taller bodied then O. tetrastigma which appear as a more elongated fish then tall.
Is there a difference between Otopharynx tetrastigma and sp. Tramitichromis intermedius? I have purchased both under both names and it is the same fish. I see it under many different lethrinops names also. Thanks in advance.