Discover the Largest Sunfish Ever Recorded

Published: September 12, 2022
© Vladimir Wrangel/
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Many people enjoy going fishing. Whether you are trying to catch dinner or just fishing for sport, there can be a sense of accomplishment in wrangling an extremely large fish.

This is why sunfish are seen as very worthy conquests among people who go fishing. Members of the genus Mola, sunfish are the heaviest bony fish on Earth.

Catching one of these enormous fish can be quite challenging. Also, they are amazing, friendly animals, so you might decide that you want to help them and play a part in saving their habitats instead. You might wonder, just how big was the largest sunfish anyone has seen? Keep reading to discover the largest sunfish ever recorded!

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How big was the largest sunfish ever recorded?

Ocean sunfish or Mola mola have small mouths and large eyes on their massive heads.
The largest sunfish ever recorded was 107 inches long and weighed 5,070 pounds.

©Anna K Mueller/

The largest sunfish ever recorded, by weight, was 107 inches (2.72 meters) long and weighed 5,070 pounds (2,300 kilograms). This sunfish was caught in 1996 off the coast of Kamogawa, Japan.

At first, this enormous sunfish was thought to be a common ocean sunfish (Mola mola). However, the true identity of the fish was addressed in a study done by Murdoch University, the University of Tokyo, and Hiroshima University. The conclusion was that the fish was a bump-head sunfish (Mola alexandrini).

Although this fish is the heaviest fish on record, it’s not the longest. In 2004, there was a female sunfish caught off the coast of Aji Island, Japan, that people measured to be 130.7 inches (3.32 meters) long. However, the people who caught this fish did not weigh her. Thus, it remains unknown whether she was heavier than the record-breaking fish or not.

In 2006, the most common type of sunfish, an ocean sunfish, was found close to Whangarei Heads in New Zealand that was longer. This sunfish was 129.9 inches (3.3 meters) long. However, it didn’t break the record in terms of weight; people estimated it to weigh between 4,850 and 5,070 pounds (2,200 and 2,300 kilograms).

More on sunfish

Ocean Sunfish, Mola mola swimming underwater with divers. They are considered to be fairly docile and gentle around human divers.
Sunfish are the largest bony fish in the world and subsist mostly on jellyfish; they are also covered in parasites.

©Martin Voeller/

Part of the family Molidae, sunfish are the largest bony fish in the world. Most of the time, when people mention sunfish, they are talking about the common sunfish or ocean sunfish (Mola mola). These fish reside in open waters, in both tropical and temperate oceans all over the world.

However, the term “ocean sunfish” can refer to either of two species: Mola mola and Mola alexandrini (which used to be known as Mola ramsayi). There are other species of sunfish as well that are closely related.

The ocean sunfish increases its weight by 60 million times the size of its egg as it grows. This fish is very often taller than it is long, growing up to 14 feet (4.3 meters) tall from the tip of the anal fin to the tip of the dorsal fin and 10 feet (3 meters) long. The ocean sunfish is related to the pufferfish. However, unlike the pufferfish, it is not poisonous. 

Eating Habits of the Sunfish

Ocean sunfish have tiny mouths with two pairs of curved teeth plates. Because of the structure of their mouths, they have to keep them open at all times, so they are not able to chew. Their diet consists mostly of jellyfish of all sizes, including tiny comb jellies, ctenophores, and big moon jellies.

The body of the jellyfish is mostly made up of water and not very concentrated in nutrients and calories, so an ocean sunfish needs to eat many of them in order to maintain its mass. However, because they are only able to eat by sucking food in and out of their mouths until it turns to mush, jellyfish are an ideal food, as they are already fairly easy to swallow.

Ocean sunfish also eat squid, salps, fish, algae, and crustaceans, although these are not the primary components of their diet.

These fish are slow swimmers that are essentially covered in parasites. There are almost 40 different types of parasites that have been discovered in or on the ocean sunfish. These include gooseneck barnacles in their throats in some cases. Sometimes, they will stay close to the surface to allow small fish and birds to eat the parasites on their skin.

Despite all of these parasites, this fish is a popular meal in many parts of Asia among humans. It’s also preyed upon by killer whales, sharks, and sea lions.

How does the record-breaking sunfish compare to other sunfish?

Baby Mola mola (Sunfish). In the first stage of development, the baby sunfish resembles small round pufferfish.
The record-breaking sunfish exceeded the average weight of a bump-head sunfish by almost 700 pounds.

©Kirk Wester/

On average, adult sunfish can grow to be up to 6 feet (1.8 meters) long and can weigh about 2,200 pounds (1,000 kilograms). While this is very large, obviously, it is much smaller than the sunfish that broke the world record.

Considering that the record-breaking fish was a bump-head sunfish, we should also look at the normal size for that species. These fish often grow to be more than 9.8 feet (3 meters) long, and it’s fairly normal for them to weigh up to 4,400 pounds (2,000 kilograms).

So compared to other sunfish, the one that broke the record is really not very long. However, the record-breaking sunfish is significantly larger in terms of weight, exceeding the average weight of a sunfish by almost 700 pounds.

How can people help the ocean sunfish?

The International Union for the Conservation of Nature lists ocean sunfish as vulnerable. However, there aren’t any laws to protect them from destruction by human beings.

In some locations, fishermen will “fin” these fish. This means they will cut off their fins since they see them as thieves of the bait they are using. After this, the fish will eventually die because it can’t propel itself through the water anymore.

Floating litter can also be a problem for these fish, particularly plastic bags. Since these fish largely subsist on jellyfish, they can sometimes mistake the plastic bags for food and end up suffocating. Alternatively, they can consume the bag. In this case, the bag will fill up their stomach so that they can no longer take in real food. They then end up starving to death.

People who want to help these animals can do so chiefly by reducing their carbon footprints. This will help preserve the current climate, which will be good for the marine habitats of these fish. Reducing litter will also potentially help them, as litter often ends up in the fish’s habitat.

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