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Please, Stop Pouring Soda on Fish Gills


A couple years ago, I saw a blog post that encouraged bass anglers to keep a bottle of Coke with them at all times. And no, it wasn’t for the caffeine high.

Instead, fishermen were supposed to use this magical elixir as a healing agent for bleeding fish. The thought was that when a fish is gill hooked or gut hooked, you can pour Coke on the wound to stop the bleeding. The soda provided a combination of carbonation and acid to clean and cauterize the sore, saving the fish from bleeding out.

This seemed too good to be true, but the fish-saving wisdom spread like wildfire. Soon, publications like Field & Stream and websites like Wide Open Spaces were promoting the theory, making it common knowledge that a Coke could bring a fish back to life.

Most recently, though, a Facebook video posted by Mystery Tackle Box garnered over 1.5 million views on the subject. It featured a shoreline angler who was holding a bass with blood-filled gills. He spoke of the healing powers of Mountain Dew, then poured the citrus soda into the fish’s gullet. The blood disappeared, and he lowered the bass into the water and watched it slowly swim away.

“And voila! Instant cauterization. Save more fish, drink Mountain Dew.”

In short order, 8,000 people had liked the video in approval, with another 12,000 sharing it with friends. This was the last straw for me, as I needed to set the record straight on this.

I reached out to a friend, Dr. Solomon David, a professor at Nicholls State University, to see what his expertise had to say on the subject.

“Coke on fish gills is as dumb as it sounds,” he explained. “My initial take is that the acidic nature of soda is bad for sensitive gill tissues. The best thing one could do is get the fish back in water that’s the appropriate temp.”

Not only is this soda theory wrong, but it’s also potentially bad for fish. The weak acid from pop would throw off the chemistry of the fish, introducing a substance that it’d never encounter otherwise. And, even if the fish’s gills were cauterized, that’d mean there’s no more gas exchange, which is crucial for a fish to, you know, breathe.

Something that everyone should have an easy time accepting is that any time a fish is out of water, it can’t breathe. These guys who keep an already struggling fish out of water to pour soda on them are just plain ignorant.

What’s more is that fish quickly lose their “slime” the longer they’re held out of water. This slime, which dries as the fish is on land, being handled or having a foreign liquid like Mountain Dew poured all over it, is crucial to their survival. If a fish really is wounded, it needs to retain this slime to help keep out pathogens and bacteria, especially when it’s already vulnerable from a wound.

Northern pike are the best example of a fish that absolutely needs that slime to fight off infections, as this species typically inhabits some of the shallower areas in lakes that are more likely to house harmful microorganisms. A fish without slime is one that’s going to be more prone to infections, and Mountain Dew isn’t helping out there, either.

As for what’s really happening, it’s likely that anglers are witnessing blood clotting when releasing fish, but it has nothing to do with Coke. Fish blood naturally clots in water and is why they can survive small dings and scrapes. Unlike mammals, who have platelets to clot blood, fish have thrombocytes. Although they have the same function, platelets don’t work under water, while thrombocytes do.

As Dr. David said earlier, the best thing you can do for an ill-hooked fish is to get it back into the water.

Still, it’s likely that many anglers will never wean themselves off of this pseudoscience, as fishing personalities continue to push this new bass-saving technique. It’s an important reminder that the biologists and physiologists who study these creatures for a living have a better idea of what’s going on than Joe Bassfisherman.

So, please, stop pouring soda on fish gills.

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