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What is a Sunfish?

Dee Saale
Dee Saale
Dee Saale
Dee Saale

There are two unrelated kinds of sunfish: saltwater sunfish and freshwater sunfish. The saltwater or ocean sunfish is also called the common mola, and it ranks among the heaviest bone fish in the ocean with an average weight of 2,200 pounds (997.9 kg). The freshwater sunfish is divided into dozens of species, such as the bluegill, the pumpkinseed and the rock bass. The freshwater species usually weigh less than one pound (.45 kg), although records have been set with anglers who have recorded fish weighing more than two pounds (.91 kg).

The common mola is native to temperate and tropical saltwater seas and oceans. It has a flattened shape and has a habit of floating near the top of the water so birds can remove parasites from its body. In addition, it has four teeth that are fused together to form a beak. Besides its flattened oval–like shape, the mola has the ability to change colors. For example, the skin is usually gray or white, but it can become lighter or darker in color when it is under attack.

Saltwater sunfish often feed on squid.
Saltwater sunfish often feed on squid.

The common mola typically eats jellyfish, squid, and small fish. In addition, they are considered non-aggressive toward humans. The largest danger they pose is damage to boats because of their hefty weight. In addition, the meat of this saltwater fish is thought to be a delicacy in many Asian countries, but care must be used to ensure the meat does not contain toxins that are poisonous, if consumed.

Largemouth bass frequently prey on sunfish.
Largemouth bass frequently prey on sunfish.

The freshwater sunfish contains dozens of species of fish. All the species are native to North America, although some species have been introduced elsewhere in the globe. These small fish are popular among anglers for sport-fishing. Depending on the species, they can have hints of blue, green, and orange, but the primary body color is typically brown or gray.

Many freshwater sunfish eat insects, minnows, and crustaceans. Interestingly, many species have been known to eat their eggs. They are usually eaten by largemouth bass, walleye, muskies, and other larger fish.

Because freshwater sunfish, such as the bluegill have populated so many lakes in North America, teams of scientists have started researching and managing the fish. Bluegill, for example, are quite prolific. Because of the abundance of bluegills in lakes, stunting has occurred. This means that the fish are smaller than they once were, changing the size of the species. Scientists hope that predators will eventually consume the smaller fish, allowing the species to return to its original size.

Frequently Asked Questions

What exactly is a sunfish?

A sunfish, also known as mola, is a unique marine species recognized for its flat body and peculiar appearance. The most common variety, the ocean sunfish or Mola mola, is the heaviest bony fish in the world, with adults typically weighing between 247 and 1,000 kg (545–2,205 lb), though some can reach up to 2,300 kg (5,070 lb) according to the Florida Museum of Natural History.

Where can you find sunfish in the world?

Sunfish are found in temperate and tropical oceans worldwide. They are pelagic, meaning they inhabit the open ocean rather than coastal areas. Sunfish are often seen basking in the sun near the surface, which helps them regulate their body temperature after deep-water dives in search of food.

What do sunfish eat?

Sunfish primarily feed on jellyfish, but their diet is varied and can include small fish, plankton, algae, and other invertebrates. Despite their large size, sunfish have relatively small mouths, which limits the size of the prey they can consume. Their diet is nutritionally poor, which is why they must eat large amounts to sustain their massive size.

How do sunfish reproduce?

Sunfish reproduction is a prolific affair. Females can release over 300 million eggs at once, more than any other known vertebrate, according to the Monterey Bay Aquarium. This reproductive strategy ensures that at least some of the offspring survive to adulthood, despite the high predation rates on eggs and larvae in the open ocean.

Are sunfish endangered?

While sunfish are not currently classified as endangered, they face threats from bycatch in fisheries, marine debris, and boat strikes. Their conservation status is listed as "Vulnerable" by the International Union for Conservation of Nature (IUCN), indicating that they are at high risk of endangerment in the wild.

What are some interesting facts about sunfish?

Sunfish are known for their unusual shape and immense size, with some individuals growing as tall as they are long. They lack a true tail and instead steer with their large dorsal and anal fins. Sunfish can also host up to 40 different species of parasites, relying on cleaner fish and even birds to rid them of these pests. Additionally, despite their bulk, they are capable of leaping out of the water, a behavior that may help dislodge parasites or evade predators.

Dee Saale
Dee Saale

Dee is a freelance writer based in Colorado. She has a B.A. in English Literature, as well as a law degree. Dee is especially interested in topics relating to medicine, legal issues, and home improvement, which are her specialty when contributing to AllThingsNature.

Learn more...
Dee Saale
Dee Saale

Dee is a freelance writer based in Colorado. She has a B.A. in English Literature, as well as a law degree. Dee is especially interested in topics relating to medicine, legal issues, and home improvement, which are her specialty when contributing to AllThingsNature.

Learn more...

Discussion Comments

live2shop

The article talks about how small the fresh water sunfish is now, usually less than one pound. Does anyone know what size they used to be - say back in the 1700s or 1800s? It's interesting that they often eat their own eggs. You'd think that would help to keep the population down!

It's good that scientists are trying to figure out a way to get the numbers down so that the size of the fish will eventually increase.

I wonder what other methods they're studying to bring the population down and the size up. If things continue as they are, the sunfish could get so small, they'd end up in goldfish bowls.

B707

A friend of mine was telling me about all the sunfish her family caught when they were visiting family in the mid west. The lakes are just filled with them. The kids enjoy fishing for them because they are so easy to catch.

She was telling me that because they are small, you have to catch a lot of them to have enough for eating right away and some to freeze for later. Just think of the time it takes to clean so many.

Apparently, they are quite good breaded and fried. I have never tasted them, so I can't comment on the taste or texture.

snickerish

@alfredo - Believe it or not but there are bluegill recipes!! How great, right?! Now you can just drop your bobber and hook down in the water next to the dock (this is where we caught all of our bluegill quickly and easily) and bam! you have dinner.

Most of the recipes I have seen are for fried bluegill, but I have also seen some more adventurous ones that involve marinating and then sauteed with various vegetables.

But I have also never seen it listed on a restaurant menu; which makes me curious as to what it tastes like.

aLFredo

When I was young and went fishing with my grandparents; I was very thankful for the bluegill because without them fishing would have been a very boring because all we ever caught was bluegill.

I had never heard them being called sunfish before!

And I would have to agree with this article whole heartedly that the bluegill have become so overpopulated that they have become smaller in size, as I felt like we were catching large goldfish when we caught them (okay a bit bigger than that, but you catch my drift)!

I was curious as to if anyone ever ate these bluegill sunfish? I have never seen it on a menu before and when we were kids we were all about the catch and release because who would want eat fish when you have a good chance of being served chicken nuggets with french fries?!

animegal

When I was really young I remember going fishing with my dad at a nearby lake. I was already excited about fishing so when I actually caught something it was pretty epic. It seemed that I was always catching sunfish though. I am not sure exactly what variety they were but they were very small and had a spot on them. My dad told me they were just sunfish.

We always ended up tossing our sunfish back in the water because my dad told me that they really weren't good for eating. He was after things like perch and trout. As far as I recall though, we rarely caught anything of real interest where we went.

wander

Sunfish in the ocean can get huge and it is rather amazing to see one up close. I had a chance to get near one of these fish when I was snorkeling on vacation a few years back. The sunfish is pretty relaxed about having people nearby so I was able to get quite a few photos.

One of the things I noticed about the sunfish was its shape, it kind of reminded me of a giant lima bean. It was also pretty dull looking considering its name. I had actually expected sunfish to be brightly colored. I guess its size makes up for the fact that it is actually not very interesting as far as its scales go.

andee

We usually spend a few weeks each summer in a cabin in Minnesota. The guys all love to fish and spend most of their time in the lake on the boat.

They usually hope to catch some bass or walleye, but it seems like they get their fair share of sunfish too. They will usually throw the sunfish back when they are really small.

I don't like the taste of fish, so don't pay too much attention to what they catch. I just know it is a good day when they can have some fresh fish for their evening meal. I make sure there is plenty of other food around for myself and the girls to eat.

honeybees

We have a pond on our property that is a good place for young kids to learn how to fish. There are a lot of bluegill in this pond, and it is not hard to catch quite a few of them in a short period of time.

We have had several young kids learn how to fish at our pond. They get so excited when they catch their first fish. If they keep at it for a little while, they can catch a bunch of them.

Most of the time they are pretty small and they throw them back in the pond, but it is much more fun for younger kids to fish when they are at least catching something.

There are also some other freshwater sunfish in our pond, but there are definitely more bluegill than anything else.

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    • Saltwater sunfish often feed on squid.
      Saltwater sunfish often feed on squid.
    • Largemouth bass frequently prey on sunfish.
      Largemouth bass frequently prey on sunfish.