Fizzing is the practice of inserting a hypodermic needle through the skin of a bass to release air from the fish's swim bladder. The swim bladder is a gas-filled sac in a bass that is used to regulate buoyancy in the fish, said Gene Gilliland, Central Region Fishery Supervisor for the Oklahoma Department of Wildlife Conservation.

“By regulating the amount of gas in the bladder, a fish can achieve neutral buoyancy and suspend anywhere in the water column - conserving energy since it does not have to constantly swim to maintain its position,” Gilliland said, adding that adjustments to the swim bladder are very slow because the gas must pass through blood vessels and bladder walls.

Why you should learn to fizz

At every depth, the swim bladder adjusts based on the water pressure. Gilliland said that when a fish is pulled from high pressure, such as deep water, to low pressure at the surface the gas bladder expands, causing over-inflation.

“If the fish is released right away they are usually strong enough to swim back down to the depth where the water pressure will recompress the bladder,” he said. “If the fish is held at the surface (such as in a livewell) then the over-inflation causes a number of problems.”

Not fizzing a bass that has been caught and placed in a livewell can often lead to problems for the fish. Gilliland said that in moderate cases, the gas in the bladder will gradually be absorbed and the fish will eventually regain equilibrium. However, more severe cases can fish exhaustion from trying to swim down but being unable too which may leave floating as easy prey on the surface of the water. The swim bladder can also become so over-inflated that it puts extreme amounts of pressure on internal organs, causing blood flow to be reduced and breathing to stop.

“The few scientific studies that have been done on fizzing bass have shown that although it is not fool-proof, it can increase the chances of survival of released fish that suffer from over-inflated swim bladders,” Gilliland said. “Many states object to or discourage the practice but it is our feeling that the benefits outweigh the liabilities and anything that might increase survival is a good thing for anglers to learn.”

How to recognize the need for a fizz

The most obvious sign a fish is having problems finding its equilibrium and needs to be fizzed is that it is floating on the surface or is unable to stay submerged. Gilliland also said a lump will often appear on the fish behind the pectoral fin that looks like they swallowed a large marble or golf ball. In extreme cases, he also said the swim bladder will distend through the throat and can be seen in the gullet.

“Any angler who has spotted a big Lake Erie smallmouth bass flopping on its side on the surface, trying to dive to safety, quickly recognizes the need. That fish probably was released by an angler who lacked the knowledge that fizzing could have enabled that fish to return to the depths,” Wollitz said. “While that fish may eventually dive, it's more likely it will die on the surface or at the very least, endure sea gulls trying to pick it apart.”

How to fizz There are two techniques for fizzing bass, through the mouth and through the side. This newsletter from the Lake Fork Sportsman's Association has great diagrams and descriptions of each method: Lake Fork Sportsman's Assoc. Newsletter “I believe mouth fizzing is more difficult to describe than to perform. It's like learning to ride a bicycle; once you are successful, you don't forget,” Wollitz said. “I was successful with my very first mouth-fizzed fish and recommend the technique.” Wollitz said he learned how to fizz through word-of-mouth advice from fellow anglers and through simple Google searches.

"Through the mouth" technique. Photo courtsey Lake Fork Sportsman's Association.

“I printed out diagrams of the inside of smallmouth bass mouths, and studied them so I was ready on the water,” he said, adding that he will be teaching the technique to his fellow bass club members as well.

If a fish is caught and released right away, it may still have enough strength to swim down to the desired depth before any problems start. However, Gilliland suggests for fish kept longer that immediate action is best.

“It is best that anglers learn to do this (fizz) in the boat and not wait for the tournament director to do it at the end of the day at weigh-in,” Gilliland said.