Dùng vợt vớt cá lên. Dò tìm hơi thở. Kiểm tra mắt cá. Kiểm tra vảy cá.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Look for signs of struggle as you place the net around the fish's body. If your fish is just sleeping, they'll wake up and try to wiggle their way out of the net. If they don't, they could be dead or very sick. Check the gills for most species. If they're not moving, the fish isn't breathing. Bettas and other labyrinth fish breathe through their mouths. If your fish is from this family, watch their bodies for up and down movements. Look at the eye as a whole. If they're sunken, your fish is dead