If the white spot is on the dorsal and the gill area, most likely culprit is bacterial or possibly fungal.
The cause of such can be shipping injury, parasite wounds, fighting, poor water conditions, etc. In this case, I would suspect poor water conditions then parasites.
I would check all my water parameters, ph, Ammonia, and nitrates, immediately. Regardless, do a 25% waterchange with new water matched in pH, temp, and Specific Gravity.
I would plan on some baretank hospitalization and medicating with a broad specturm medication. IME Maracyn I and Maracyn II along with MarOxy is not too distressing when mixed together. Read the current directions and make your own choices though.
Hopefully they are both still eating well, but they both look a bit thin in the pictures.