How to Vent a Fish

If fish are not vented properly before they are returned to the water, serious injury or death can occur.

Many fish have a swim bladder, which allows them to control at what depth level they swim in the water. When they are caught and brought quickly to the surface, this swim bladder fills quickly with air. If the fish is returned to the water in this state, it will be unable to function properly, which may result in death or injury. To avoid this situation, many types of fish need to be properly vented before they are returned to the water. Venting is the process of releasing gases from the fish's swim bladder to return it safely to its habitat.

Things You'll Need

• Venting tool

Instructions

1. Determine the type and condition of the fish. Species of fish with large swim bladders benefit the most from venting, but various types of fish can benefit from this process. A fish should be vented if it is bloated and unable to control its buoyancy to return to its habitat or if its stomach is pushed out of its mouth.

2. Hold the fish gently but firmly. Do not squeeze the fish too hard, but be in control of its movements.

3. Insert the venting tool 2 inches from the base of the pectoral fin at a 45-degree angle. Only insert the tool far enough to release the gases. Pushing it any further could harm the fish. You should be able to see the bloating decreasing and hear gases being released. If the fish is very bloated, use some pressure on the abdomen to aid in releasing the gases.

4. Maintain a strong grip. Hold the venting tool tightly so that any movement from the fish doesn't cause harm.

5. Return the fish to the water quickly so that it can recover normally. If it doesn't immediately begin to take to the water, hold its head down and allow the water to move over its gills until it is able to swim.

Tips & Warnings

• Start the venting process immediately after you determine it is necessary for the best chance of success. When you begin, do not push the stomach back into the fish if it is visible. The stomach will return to the proper position at a later time, once you have properly vented the fish.

• Clean your venting tool with chlorine bleach after use.

• Place a cover of some sort over your venting tool to avoid injury during storage.

• Have a plan for releasing fish before you catch them. This will speed up the process.

• Handle the fish as little as possible to avoid harming it.

• Too much handling of the fish can be dangerous to the success of this process. Carefully handle the fish and return it to the water as quickly as possible.

References

• Florida Sea Grant: Venting: A Guide to Releasing Reef Fish with Ruptured Swim bladders
• Florida Sea Grant: Catch and Release Fishing: Recompression and Venting