The Terme di Diocleziano was part of the Roman bath complex, and one far corner of the museum houses works that actually decorated these very baths in ancient times. Not surprisingly, many of the works followed an aquatic theme. What was a bit surprising, though, was the combination of very accurate and wildly fantastic subjects and rendering. Most of the fishes in this mural are species that were considered highly palatable, sometimes even farmed by the Romans. However, there is no consistancy of perspective between them. Small fish and crayfish are depicted the same size as larger fish. Also, note the man riding a dolphin in the middle of the work.
Clearly this is a battle between a squid, a shrimp, and some sort of eel-like fish, but either they are all meant to be very tiny or the crustacean is meant to be one seriously large prawn. This fresco is from 2nd-century restorations to the baths.
Mosaics were common, too. Following the theme of semi-realism, this mosaic is attempting to depict life along the Nile. It's actually not a terrible rendering of a hippo, although appearing a bit more fierce than they look in real life.
This mosaic shows two different thoughts on the appearence of Satyrs - the first an older, Pan-like creature and the second with a more rounded face. This second type seems to have influenced Renaissance depictions of satyrs and Bacchus.
The art of miniature mosaics sometimes crops up in these early works, too. This is simply a detail of a larger piece.
Eric getting a close look at Dionysus. This one doesn't have the long flowing hair, but he does have the snake and the stalk of grain, which are symbols of Dionysus.