5 Most Dangerous Sea Fish

Last Updated: 17.06.19


Diving in the vast seas can be an experience one might never forget. While some may do it only once and never get close to it again, some people just want more and more of that diving thrill. Swimming among corals and a variety of sea creatures just leaves you astonished of the beauty that lies beneath the waters of the sea.

There’s plenty of colorful and playful fish for you to see while diving. However, not all of them are keen on swimming alongside you. Some of them can be very dangerous, and while you might mean no harm to them, that doesn’t mean they won’t get scared and feel like they’re in danger.

Today, we’ll be showing you five of the most dangerous fish that can be found in the sea – make sure to avoid them so that both you and the fish will be safe.


Because of the way it looks, this fish can be easily mistaken for just another rock on the bottom of the sea. You should, however, be very careful when it comes to what you’re stepping on, as the result can be fatal.

Commonly found in the Indo-Pacific ocean, the Stonefish can usually be spotted – if you have a sharp eye – near corals and rocks. Because of the bumpy texture of their skin, looking just like warts, it’s pretty easy for them to turn invisible.

The most dangerous thing about them is their dorsal spine which, once stepped on, will start injecting venom into your body. The wounds that result from an encounter with a Stonefish are described as incredibly painful and they can also be fatal. Therefore, the next time you’re out snorkeling, watch your step!


Moray Eel

The Moray Eel is commonly found in the Indo-Pacific ocean, just like the Stonefish. They can grow up to five feet in length, but there is one Moray Eel species, the Thyrsoidea macrurus, that can reach a length of 11.5 feet.

They are usually seen around rocky areas, places in which they can easily hide from any predators. The Moray Eels come with a variety of vivid colors that make them a target that’s worth following by divers so that they could get a closer look.

One of their characteristics is that they lack pectoral fins, which is why they can be easily identified. In terms of dangerous features, they have a wide jaw that shelters strong, razor-sharp teeth. Because of their wide jaw, they can hold onto their prey before devouring it. While it would be hard for a Moray Eel to devour your leg, they can give you some serious wounds if you accidentally startle them.

They are dangerous when they bite you, but also dangerous when you bite them. It is recommended that you never try eating a Moray Eel, as their flesh contains toxins that can lead to certain illnesses and, in the worst case, even death.


Great White Shark

You’ll have to bring with you the most effective sonar system you can find out there in order to avoid an encounter with one of these big fish – as the Great White Shark is responsible for a large number of deaths in Australia and the United States. In Australia, from all of the Great White Shark attacks, 60% of them are fatal, while only 7% of them are so in the United States.

You’ve probably heard of or seen someone doing cage diving – or even more extreme situations, where people actually swim with these sharks. You’ve also seen plenty of news reports of sharks attacking the people in cages or those swimming with them even if they were not provoked.

This has led to many people thinking that the Great White Shark is one of the most dangerous sea creatures. However, that’s not entirely true. The only reason we are prone to be attacked by such a fish is that we resemble their natural prey – namely, sea lions and seals.

The bite of a Great White has left many people without one or two limbs. The only thing that has granted their survival is the fact that this shark never takes a second bite. It’s either a one bite kill or they’re out. Of course, being bitten by one of them means that you will have to be taken to a hospital as soon as possible as blood loss will eventually cause death.

Salmon fishermen admire the seascape, Bristol Bay, Alaska, USA

Puffer Fish

This is probably one of the tiniest fish you’ll have to fear while swimming in the ocean. Also known as blowfish or swellfish, the Puffer will inflate itself if it’s being threatened or stressed by anything in the surrounding environment. Their skin is full of prickles ready to sting you if you get too close – so don’t!

The main feature that makes them one of the most dangerous sea fish out there is the toxin that’s contained by their internal organs. Called Tetrodotoxin, it’s highly toxic and fatal. That’s why the Pufferfish is usually not eaten. However, in Japan, it is considered a delicacy and people will pay enough in order to get to taste one of these fish.

You do have to make sure that the chef that is preparing the Puffer is well trained and experienced, as one wrong move of the knife and the meat will be as toxic as when the fish was alive.


Red Lionfish

This is yet another species of fish that is commonly found in the Indo-Pacific ocean. They can grow up to be 12 inches long and are very beautiful to look at. They come with colored stripes that resemble the coat of a lion – obviously – with even more beautiful dorsal and lateral spines.

However, it’s the spines you should take into account if you happen to come across a Red Lionfish. In case you are an angler, you should opt for a more resilient pair of pants, and not your basic fishing shorts, as these spines are very venomous.

The wounds caused by the sting of the spines can be very painful and can even cause death. When startled, the Red Lionfish will only spread its fins, warning you that you should stay back. If you get closer and manage to make them feel threatened, they will attack you.

If diving, make sure you are aware of your surroundings and stay away from this small – yet deadly – species of fish.



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