Which lines in this excerpt from Elizabeth Bishop's "The Fish" show that the fish has given up struggling for survival after living a hard life?

I'll just post an excerpt of the poem "The Fish" by Elizabeth Bishop. The excerpt would show that the fish has given up struggling for survival after living a hard life.

"I caught a tremendous fish

and held him beside the boat

half out of water, with my hook

fast in a corner of his mouth.

He didn’t fight. ⇒ The fish gave up

He hadn’t fought at all. ⇒ struggling for survival

He hung a grunting weight, ⇒ after living

battered and venerable ⇒ a hard life

and homely. Here and there

his brown skin hung in strips

like ancient wallpaper,"