I think different species, possibly even different genera. However, I don't pretend to know.
The fish in the second picture (which shows well its side), shows a central (dorsal) line of scales bearing protrusions (like spines) along the the fish's length. Then, there is at least one more row of similar spines on the side of the fish, about mid height along the body; potentially (not sure about this one) one more row below.
The fish in the third and fourth pictures (same animal) is much smoother, with no visible rows of scales bearing protrusions as the previous fish.
I would say they are different species at least.