Sunfish vs Bluegill : How to Identify Different Species

Oftentimes, people confuse Sunfish and Bluegill as the same type of species because of their similar resemblance. Even though there are similarities between these two species, there are also very clear distinctive features between them.

From their natural habitats to their respective sizes, there are lots of subtle yet distinct differences between Sunfish and Bluegill.

In this article we will see a Sunfish vs. Bluegill comparison. By the end of this article, you will be able to properly differentiate between the two species. The subtle contrast between them will become evident to you.

Reason for Confusion

As mentioned before, one of the prime reasons why people confuse Sunfish and Bluegill as the same is down to their similar appearances. Even though there are differences between them, the differences are quite subtle and difficult to notice at first.

Sunfish Habitat

Besides their noticeable similarities, these two fish also come from the same family.

The term “Sunfish” is usually used to refer to a lineage of fish that live in freshwaters and are ray finned. The Latin name used to refer to this family is Centrarchidae.

Under this Centrarchidae, there are eight distinct genera. One of these eight is Lepomis or Sunfish. Many of these species carry the name “sunfish” with them, even though they might be classified in a different manner.

In colloquial terms, there are, in total, thirteen different species that people refer to when they use the term “Sunfish”. One of these thirteen species is the Bluegill. There are lots of similarities in the appearances of these subspecies, and that is why people use their names interchangeably.

From this, we can say that: all Bluegills are Sunfish, but not all Sunfish are Bluegills.

Characteristics of Sunfish

The term Sunfish is used to define a rather large family of species. The most commonly referred to Sunfish is the Mola Mola or Ocean Sunfish. Here are some characteristics of the Ocean Sunfish:

Habitat

The adult ocean sunfish like to live in the open ocean. They are saltwater species. They are found in various temperate and tropical water bodies all around the world.

Sunfish

Occasionally, these fish venture into coral reefs to be cleansed off parasites that might be living on their bodies.

Lifespan

The exact longevity of ocean sunfish is yet to be determined. Certain species of this genus might live from eighty two to one hundred and five years.

Behavior

The Ocean Sunfish is a creature of solitude. They lie roaming about on their own. Sometimes they do travel in schools, but that only happens when they are being cleaned by other fish.

Appearance

They have a large body that is both compressed and oval shaped. Their body is devoid of scales and their skin is very thick, and rubbery. Their body is ectothermic and is bilaterally symmetrical.

They have a small mouth that has teeth that form a structure similar to a beak.

Size and Weight

They can grow up to 3.1 meters, about 4.26 meters in height. They can, at maximum, weigh up to 2235 kilograms.

Reproduction

Very little is known about their reproductive behavior. They usually breed in the ocean as they live in salt waters.

The eggs of female Ocean Sunfish are rather miniature in size. They have a diameter of approximately 0.13 centimeters. The females can produce up to three hundred million eggs in each mating season.

Food Habits

Ocean Sunfish are carnivores. They feed on jellyfish, zooplankton. They often travel to places of higher altitude where zooplankton usually migrate to during the seasons of summer and spring.

Sunfish Food Habits

They also consume aquatic plants such as macroalgae.

Characteristics of Bluegills

Bluegills are a subspecies of the Sunfish family. Here are some characteristics or traits of Bluegills:

Habitat

Bluegills live in temperate freshwater. That includes places such as lakes and rivers. They prefer to live in water bodies where the stream is rocky and moves in a relaxed manner. Bluegills are freshwater fish and can only tolerate salinity upto eighteen percent. They are often found in very deep beds of weeds.

Lifespan

Bluegills generally live from four to six years in open spaces. But under captivity, this longevity can extend from eight to eleven years.

Appearance

The body of Bluegills is yellow, with yellowish-green, deep green, or greenish brown at the top of their body. They have a very small mouth on a short head and this gives them a rather distinctive look. 

They have either a dark purple,or blue colored material on their cheeks. They get their name “Bluegills” from the flashy material that is present on their cheeks.

The adults are typically between ten to fifteen centimeters in length. Sometimes they could even grow as much as forty-one centimeters.

They are ectothermic, and their body is bilaterally symmetrical. The younger Bluegills are a rather paler version of their adults. They might have very faded, vague purple sheen.

Reproduction

The breeding season of Bluegills usually occurs between the months of May to September. The females carry upto fifty thousand eggs at a time. It takes a few days, on average three, for the eggs to hatch. After the eggs hatch, the offspring leave the nest after seven days. Usually, the optimum temperature for spawning is between seventeen to thirty-one degrees.

Characteristics of Sunfish

The males guard the nests both before and after the females have laid their eggs. Parental care also involves chasing away predators. Both the male and female reach sexual maturity at between one and two years of living.

Females lay eggs in several nests, whilst the eggs built by one male can be used by multiple females.

The mating system is polygynandrous.One female will mate with multiple females, whilst one male will also mate with multiple females.

Food Habits

Bluegills have a very small mouth. They are carnivores and they consume different types of aquatic insects, worms, snails etc. They also feed on aquatic plants such as algae.

Younglings eat worms and zooplanktons. They consume their food in a clandestine manner, whilst the adults feed out in the open. 

Sometimes, when there is a shortage of food, they often consume their own eggs.

Bluegills play an important role in the ecosystem, as they consume smaller animals. Many times, they are the food of other larger animals.

Comparison: Sunfish vs. Bluegill

Reason for Confusion

The differences between the two can be spotted across a variety of categories. Below, we will see the differences between them under individual aspects:

Habitat

One of the distinctive differences between the two is their place of living or accommodation. Bluegills are found in freshwaters, whilst Sunfish are found in saltwater areas, such as the sea.

Usually, Bluegills make their homes in rivers and lakes, whilst Sunfish make their homes in tropical water.

Food

As expected, they both feed on aquatic organisms. Sunfish are mostly carnivores. They consume saltwater animals that they find, such as jellyfish. Bluegills, on the other hand, most feed on aquatic insects. Sometimes, they might even consume their own eggs. This happens when there is a shortage of food. They also eat algae.

Scientific Names

Bluegills are a part of the Sunfish family. As mentioned before,all Bluegills are Sunfish, but not all sunfish are Bluegills. They are both a part of the Centrarchidae family. The scientific name of Sunfish is Lepomis, and the scientific name of Bluegill is Lepomis Macrochirus. 

Some other names that the Bluegill is called by: Bream, Sunshine, Copper Nose.

Appearance

Even though Bluegills are from the Sunfish family, there are a lot of notable differences in their appearances from other species of the family. 

Bluegills have a yellow body, with yellowish-green, deep green, or at times greenish brown at the top of their body. Their mouth is very small, and this gives them a rather distinctive look. They have either a dark purple,or blue colored material on their cheeks. The mouth of Sunfish is much larger than that of Bluegills.

Hybridization occurs in other sunfish species. But it does not occur in Bluegills.

Reproductive male Sunfish are generally white, silver-grey or brown in color. On the other hand, reproductive male Bluegills have deep purple or dark colored tones on the upper part of their body.

Size and Weight

Bluegills usually grow up to be six to ten inches in length, and can weigh a maximum of four pounds. On the contrary, sunfish can grow up to be ten feet in length. They can weigh up to 2000 pounds.

Sunfish are considered to be the largest bone marine fish that are found in saltwater. 

The small size of bluegills helps them to workout very easily in the aquatic environment. They can also move faster than sunfish because of their smaller stature.

Behavior

Bluegills move around in groups. They are reliant on density. In other words, their size decreases if their number increases. 

Sunfish, on the other hand, are rather solitary beings. They only move about in groups when they are cleaned by other fish.

Conclusion

People use the terms Sunfish and Bluegills quite interchangeably. They assume both the terms represent the same type of fish. But as we have seen from this Sunfish vs. Bluegills article, there are a lot of distinctive characteristics between them. 

Starting from appearances to their preferred habitats and to their reproductive mechanisms, there is a lot of distinction between them.

In order to properly differentiate you must first learn their individual features, and then know their subtle distinctions.

Otherwise, whether for fishing or for consuming purposes, you might end up catching the wrong type of fish. For spawning purposes, do proper research on the type of environment that is conducive to their living and reproductive habitat.

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