cunning devices

Fishing involves trickery - baited hooks and artificial lures - but fish, it seems, use ruses too. In the second century AD the Greek poet, Oppian, wrote the Halieutica, a long work focused on the fisherman's art. Book III of the poem (which begins with an invocation to Hermes. the god of both tricks and fishing) emphasises exactly this point:

Fishes ... not only against one another employ cunning wit and deceitful craft but often also they deceive even the wise fishermen themselves and escape from the might of hooks and from the belly of the trawl when already caught in them, and outrun the wits of men, outdoing them in craft, and become a grief to fishermen.

The poem is mainly concerned with sea-fishing but it does talk about angling as well as fishing with nets. The following are tricks played by fish when caught with a hook and line:

      The Basse, when smitten by the point of the bent hook, leaps on high and incessantly presses its head violently on the line itself, till the wound becomes wider and it escapes destruction.
      The mighty Orcynus employ a similar device. For when they have seized the jaw of the guileful hook, swiftly they strain and rush to the nether depths, putting pressure on the hand of the fisher; and if they reach the bottom, straightway they beat their head against the ground and tear open the wound and spit out the barb.
      But when giant fishes swallow the landed hooks — such as the tribes of the Ox-ray and the Sea-sheep and the Skate or the sluggish race of the Hake — they will not yield to it but throwing their flat bodies in the sands they put all their weight upon the line and cause trouble to the fishermen, and often they get free from the hook and escape.
      The swift Amia and the Fox-sharks, when they are hooked, straightway hasten upward to forestall the fisher and speedily bite through with their teeth the middle of the line or the extreme hairs. Therefore for them the fishermen forge a longer socket on the hook, as a protection against their teeth.
      The Cramp-fish, moreover, forgets not its cunning in the pain of being struck, but straining in its agony it puts its flanks against the line, and straightway through the horse-hair and through the rod runs the pain which gives the fish its name and lights in the right hand of the fisher; and often the rod and the fishing-tackle escape from his palm. Such icy numbness straightway settles in his hand.

Apparently the 'Cramp-Fish' is what is now known as an electric ray  and, if you look hard, you can see one among the fish represented in this mosaic from a Roman villa in Catalunya (3rd century AD). (I've turned the contrast up a bit, so it's easier to see.)