Ever catch a cat from deep water and its belly was bloated looking and very firm? When a fish is in deep water the air in its swim bladder is compressed from all the pressure around the fish. When the fish is brought up quickly this compressed air expands as the pressure comes off of it and causes the fish to bloat. Normally a fish can equalize the pressure on is own as is rises, but not when pulled up quickly as often happens when we catch one. If possible try to bring the fish up slowly to let the fish release the trapped air on its own, you will see air bubbles coming to the top of the water as the fish releases this trapped air. A fish that is bloated like this cant dive until the air is released either naturally, or with a little help and will struggle on the surface and could die. Sometimes a cat will burp on its own when a little gentle pressure is applied to its belly by a hand or when lying on the bottom of a boat. If not, a small pipe can be inserted gently down it's throat until the air is released. Be careful not to have your face in line with the pipe because often a little gift may come out along with the air. I use a ½ inch pvc pipe with the ends smoothed off for this. You will hear a lot of people say to stick them with a needle.. DONT DO THAT! IT WILL KILL THEM. They will swim away at first, but it inhibits their ability to properly swim and suspend and eventually leads to mortality. Our last tournament we had to burp 3 of the fish we caught, most we brought up slow enough that the fish would release the pressure on its own. Just a little tip for people fishing deep water.