What Happens if You Leave a Hook in a Fish?

As fishermen, we have all been in that unfortunate situation where the hook on our fishing line remains in the mouth of a fish. We try our absolute best to try to remove the hook, but different obstacles can sometimes prevent us from doing so successfully. This topic has garnered a lot of research over the years and has certainly created some controversy. Can the fish survive with a hook in its mouth? Studies have shown that they can.

Different Reasons for Leaving a Hook in a Fish

No fisherman ever wants to leave the hook in a mouth of a fish. When releasing a fish, you want to assure that the fish stays alive and returns to their ecosystem. However, when you can’t remove the hook, it’s usually the best decision in that moment. Here are the several reasons that would cause an angler to leave a hook in the mouth of a fish:

  • Line Breaks – For this instance, an angler could be battling a fish that is hooked on his/her line until suddenly, the fish breaks free from the line. This may occur if the teeth of the fish break a line (always fish with a leader), or the fish gets caught into structure under water, such as rocks or a reef. Now, the fish is no longer on your fishing line, but it could still have the hook in its mouth.
  • Fish Swallows Hook – Sometimes, we hook the fish a little too well. In these situations, the fish swallows the entire hook. However, if you want to try to attempt to retrieve the hook, you could potentially cause greater harm to the fish. At this point, leave the hook rather than accidently ending the life of the fish.
  • Dangerous or Large Fish – There are many fish in the ocean they we should avoid close contact with. If you happen to hook one of these types of fish, it is probably safer to purposely release the fish by cutting the line. In some situations, the fish will be better served staying in the water rather than being exposed to the air for a long period of time. In this instance, leaving the hook in the fish could be beneficial to both parties, both the angler and the fish.

Negative Effects of Leaving a Hook in a Fish

Throughout my time fishing, I was always told that a hook will eventually fall out of the fish on its own. A lot of studies have been done, but the evidence still shows that a lot of fish will still not make it, even if the mortality is slightly delayed.

Hook Poisoning – Back in the day, fishing hooks were made of a material known as tin-cadmium. These hooks contributed to higher morality rates for fish because they would actually receive cadmium poisoning. Luckily, fishing tackle companies have made some much-needed innovation with their development of hooks. Further analysis shows that bronze hooks may be the best option, as they show the highest likelihood of falling out of the mouth of a fish.

Blocked Esophagus – When the fish returns to its normal eating habits, the food itself can cause the hook to be pushed further down the throat and block the esophagus of the fish. To this day, hooks are still very sharp and can do some real damage to an esophagus. Depending on the circumstance, sometimes the hook will be accompanied by a portion of the fishing line which remains tied to the hook. Interestingly enough, the length of the line actually benefits the fish and can help force the hook to the opposite side, allowing the fish to eat safely. Obviously, it is still isn’t an ideal scenario, but the further the fish can prolong its life with the hook, the greater likelihood the hook with eventually fall out.

Can a Fish Survive with a Hook in its Mouth?

Fortunately, most fish are able to survive after being released with a hook in their mouths. In a study that was conducted with tagged fish, the data showed that most fish are able to shake out the hook in only a couple of days. The positive effects of the salt water such as its salinity and the current of the water can help contribute to the hook being removed quicker.

Of course the scenario can impact different fish in various ways. According to New England Sportsman, stripers form a scare tissue in the location of where the hook penetrates their mouth. The irritation creates such a disruption to the mouth of the fish that it causes a large fibrous scar to form with enlarged tissue. At this point, the chances of the hook naturally falling out significantly drop. This wound, that only continues to get worse, can develop into bad types of infections that contain unsafe bacteria. This bacteria can develop quicker from the rapid change of water temperatures during the spawning season of a fish.

What happens if the fish swallows the hook? We mentioned earlier that releasing a fish that has swallowed a hook is a safer decision compared to trying to retrieve the hook. A fish has a very strong stomach and the hook can actually erode away over time once it reaches the stomach. Their body has enough acidic enzymes to naturally break down the materials that make up a hook. A hook will take time to rust away in the stomach and is dependent on the thickness of the hook. The thinner the hook, the quicker it will dissolve. This option is way better than trying to force pliers into the digestive tract of a fish.


When in doubt, always try to remove the hook, especially if it is easy to do. For all fishermen, we recommend keeping a pair of pliers with your fishing tackle to help seamlessly remove a hook from a fish. Different hooks and lures have their own unique impacts on a fish depending on the material and the sharpness of the hook. We enjoy the sport of fishing and that opportunity is made possible by the fish that are available in the waters that we fish. If we all devoted just a little extra effort to learn more about safely releasing fish, then more fish will stay alive during a catch and release.

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