Securely attached or fixed = I caught a massive fish and held him next to the boat half out of water, with my hook fast in a corner of his mouth.
The hook needs to grip the fish so that the angler can pull him out of the water. As the hook is described as fastened to the fish's mouth, it implies it is affixed there.
Compressed or crumpled = A green line, frayed at the end due to a break, two thicker lines, and a slender black thread still crimped from the tension and snap during its break when he got away.
The term crimped indicates something being compressed or wrinkled. A crimping iron used on hair creates ridges, while a straightener makes hair flat, and a curling iron adds curls.
Sullen or displeased = I admired his sullen face, the mechanism of his jaw, and then I noticed five old pieces of fish-line trailing from his lower lip —if one could term it a lip, grim, moist, and weapon-like.
The fish's face reveals he has been caught before, evidenced by the several old fish lines hanging from his mouth. This indicates he’s likely furious since it’s probably not his first time being reined in.
