Fun Round Goby Facts For Kids

Moumita Dutta
May 18, 2023 By Moumita Dutta
Originally Published on Aug 05, 2021
Edited by Katherine Cook
Round goby facts are interesting to read.

A round goby (Neogobius melanostomus) is a euryhaline goby fish of the Gobiidae family, typically found in freshwater lakes, rivers, and streams. A round goby's habitat mostly consists of huge rocks, gravel, sand, and crevices to hide. This fish is a bottom dweller and can go to a depth of 162 ft (50 m) in winter.

The round goby is native to Eurasia and is usually found in the Black and Caspian seas. However, round gobies are known as an invasive species as they expanded their range to occupy the Baltic Sea and invaded the Great Lakes in North America. This means they have a large distribution of population.

A round goby usually has mottled gray skin, with brown and olive-green markings on them. A male round goby has darker splotches on its skin.

To distinguish this fish, a black spot can be seen on the front of its dorsal fin. Their eyes bulge out of their large frog-like head and they have fused pelvic fins, that create a suction disk on their belly. The average length of a round goby is around 7 in (18 cm).

They prefer to be in a warmer temperature of about 86 F (30 C). This aquatic fish prey on various zebra mussels, fish eggs, mollusks, sculpins, and darters.

Read on to discover interesting facts about the round goby. If you enjoyed reading this article, do consider reading our articles on brown trout and wolffish.

Round Goby Interesting Facts

What type of animal is a round goby?

The round goby (Neogobius melanostomus)  is a small fish with a mushy body.

What class of animal does a round goby belong to?

Round gobies belong to the class Actinopterygii. Species belonging to this class are also called ray-finned fish, based on the physiology of their fins.

How many round gobies are there in the world?

While there is no exact estimate, the round goby's population in native and invasive grounds is in the millions.

Where does a round goby live?

Round gobies are native fish of the seas of Marmara, Black, Avoz, and the Caspian Sea, spreading into the tributaries of these water bodies.

In the early 1900s, this fish species was discovered in the St Clair River and since then, they have been an invasive species in the St Clair River, the Great Lakes, and the Chicago River as well.

They are also found in the Baltic Sea.

What is a round goby's habitat?

A round goby habitat is freshwater regions such as rivers, lakes, and streams. These bottom-dwelling fishes are found living under huge rocks in their native range where they can hide well. They prefer warmer temperatures which are around 86 F (30 C).

They can also live in water bodies with low oxygen concentrations and in ballast water, which is how round gobies were able to invade the Great Lakes.

Who do round gobies live with?

A round goby is typically solitary and does not let any other kind of fish in its native range. Living together in small groups of their kind gives a round goby control of its territory. This ranges to a few miles.

How long does a round goby live?

The round goby life cycle, in the wild and captivity, usually is up to four years. Females live up to three years.

How do they reproduce?

In this fish species, the spawning season goes from April to September when a female fish spawns roughly five to six times in one season. A young male round goby attains its sexual maturity in three to four years, whereas a female round goby in two years.

Male round gobies migrate to a more shallow part of their habitat and attract females to mate with them.

Male round gobies change their skin color to dark black in the spawning season. Round gobies are polygynous, due to which multiple females leave their eggs in one male's nest.

The average clutch size of round goby eggs is about 2500 eggs. These eggs hatch in about 20 days. Males protect the eggs and the young from predators.

What is their conservation status?

The IUCN Red List has categorized this species as Least Concerned. It is present abundantly across the globe. The round goby, an invasive species of North America, has several population control measures.

Round Goby Fun Facts

What do round gobies look like?

The round goby physiology can be described as soft-bodied with a large head similar to a frog. This invasive species of fish has big eyes bulging out of its head and a spineless dorsal fin.

The round goby size is in the smaller range, with the length being 5.9 in (15 cm), but some adult fish reach a length of up to 11.8 in (30 cm).

Adults are of mottled gray skin with dark brown and olive green markings. Males usually have black splotches. The dorsal fin on this fish usually has a black spot on the front of it.

This fish also has fused pelvic fins that form a suction disk and can grow to a length of 7 in (17.8 cm).

Underwater view of round goby fishes.

How cute are they?

Having a soft, blotched body with dark colors, eyes bulging out of their head, and a big mouth, they might not be the cutest fish out there.

How do they communicate?

Round gobies typically communicate via visual and chemical channels.

How big is a round goby?

The typical length of an adult round goby is around 7 in (18 cm), and the length increases with their age. Some fish may grow up to 11.8 in (30 cm) in length. Males are usually bigger than females.

How fast can a round goby swim?

An adult round goby swims in the river in a swift shooting manner which looks like they are hopping from one place to another.

How much does a round goby weigh?

An adult round goby typically weighs in the range of 0.1-o.2 lb (5-80 g), depending on their size.

What are the male and female names of the species?

There are no specific names for male and female species of round gobies.

What would you call a baby round goby?

A round goby baby is called a 'fry'.

What do they eat?

The round goby diet mainly consists of mollusks, worms, and zebra mussels. They also feed on insect larvae and crustaceans. More than 50% of this fish's diet comprises mussels. A zebra mussel is their favorite! It looks for food at night and can navigate the waters at night because of its lateral line system.

This invasive round goby species feed voraciously on blue mussels in the Baltic Sea, impacting their population. In the Great Lakes basin, they eat the eggs of lake trout, darter species, and sculpins.

The list of round goby predators includes sport fish, walleye, and brown trout.

Are they aggressive?

Yes, this fish species is quite aggressive compared to its size. They prey on any small or young fish that try to invade their river or stream territory. You may even call a round goby an 'egg predator'.

Would they make a good pet?

These round gobies are quite poisonous and they are not known to make good pets. In fact, according to the government of Ontario, it is illegal to possess a live goby fish.

Did you know...

If you ever catch a round goby, you can kill it as it is an invasive species with increasing populations and it has to be controlled.

The round goby is quite poisonous as its diet consists of quagga and zebra mussels. They contain a large number of irons in their body, meaning that it is not recommended to eat this fish species.

A round goby has a similar appearance to its cousin, the tubenose goby.

To distinguish between a round goby vs. walleye, you need to know that a walleye fish is much larger, has sharp teeth, and is not poisonous. Its eyes have a certain pigment that reflects light.

Round gobies are controlled by the government. Regulations such as electrical barriers are used to stop their movement.

Moreover, the public is educated on how to identify a goby fish. This helps not only report and survey the area but also warns people to eat them as food or use them as bait. In the United States, New York State and Michigan have regulations regarding round gobies.

How did the round goby get to the Great Lakes?

Round gobies are native species to the Black and Caspian seas and are also found in their tributaries.

In 1990, it was recorded that this fish was introduced to North America through ballast water. This species was discharged by cargo ships to St Clair River and eventually became an invasive species in the Great Lakes basin. Today, this species has an estimated population of millions in these water bodies.

How do round gobies affect the ecosystem?

Round gobies impact the ecosystem of native fish negatively. It has been conjectured that round gobies could deteriorate the North American aquatic ecosystem.

These aquatic species eat the eggs of a considerable number of native fish or small fish, such as zebra mussels, sculpins, logperch, and snails, depleting the populations of native species. Owing to its invasive nature, it meddles with the distribution of native fish in its territory.

The economic impact of the round goby for anglers is negative. This species is a big inconvenience as baits get lost due to this species of fish. Anglers may also mistakenly catch gobies instead of sport fish.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other fish including monkfish or black dragonfish.

You can even occupy yourself at home by drawing one on our Round Goby coloring pages.

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Written by Moumita Dutta

Bachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

Moumita Dutta picture

Moumita DuttaBachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

A content writer and editor with a passion for sports, Moumita has honed her skills in producing compelling match reports and stories about sporting heroes. She holds a degree in Journalism and Mass Communication from the Indian Institute of Social Welfare and Business Management, Calcutta University, alongside a postgraduate diploma in Sports Management.

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