Understanding Barotrauma



Barotrauma is when a fish’s swim bladder, sometimes called an air bladder, expands creating pressure on vital organs and can lead to the fish’s death.  Death due to barotrauma can be avoided by releasing the excess air from the bladder, also known as fizzing.

When you catch a bass out of depths usually greater than 20 feet, barotraumas can occur. In tournament situations, you try to get the fish in the boat as soon as possible and into the livewell. 

Rather suddenly, you will know if your fish is experiencing a barotraumatic episode.  This can be recognized by the fish’s behavior in the livewell. Symptoms are, floating upside down, or on its side, trying frantically to swim down but can’t, sometimes the fish maybe beneath the surface, but its caudal fin is upward and the fish is exerting more energy than normal to keep its head down.  In extreme cases, the belly will swell and the stomach will protrude from the fish’s gullet.  This means the swim bladder has too much air for the fish to maintain neutral buoyancy. 

Neutral buoyancy is desired by fish to hold parallel, swim and move around as they wish. The swim bladder is normal when small, as you bring the fish up towards the surface more rapidly than it would ascend on its own, the swim bladder will expand.  Fish that can’t dive down, for all intents and purposes, become vulnerable to prey such as birds, and even boats cruising by, and their own stresses which can lead to death.


To fizz a fish means the removal of excess air; you cannot remove enough and you can remove too much. Texas Parks and Wildlife did a study on barotrauma of largemouth bass and the practice of fizzing. 

In this study, they found that bass weighing less than three pounds need to be fizzed from three to five seconds and bass weighing more than three pounds fizz between five and eight seconds. This is just a general guide, you will notice within 15 to 30 minutes if a fish still has excess air in its bladder, because it will still be floating, in which case you would fizz again.


There are two ways to fizz a bass, through the mouth or on its side. The Texas Parks and Wildlife study showed that there was a 14 percent higher survival rate when bass were fizzed on their side. You need a 1 ½  to 2 inch, 16 - 18 gauge needle.  In the accompanying video, I give you a quick idea about a bass’ anatomy and how to fizz a bass from the side. 

Most people who have shown me how to fizz a bass usually go through the mouth and between the crushers, but since so few know how to go from the side and it has been proven a safer method, I figured I should focus on that technique for this particular video.  

Taking the time to fizz a bass is a simple, yet necessary, step to keep our fish alive and thriving, for future generations.