Common bully facts for kids
Quick facts for kids Common bully |
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The common bully (Gobiomorphus cotidianus), also called toitoi in Māori, is a special fish. It is found only in New Zealand. This means it is endemic to New Zealand. You can find common bullies all over the country.
This fish is quite small, usually growing up to 15 cm long. It can live in different types of water. These include fresh water, salt water, or even brackish water. Brackish water is a mix of fresh and salt water. Common bullies often live near the bottom of rivers and lakes. They prefer water that moves slowly or moderately. This makes them the bully species you are most likely to see.
It can be tricky to tell common bullies apart from other bully fish. But one good clue is the vertical lines on their cheeks. They also have special patterns of scales and pores on their heads. However, these are hard to spot in the wild. Common bullies eat small creatures that live on the bottom. Their diet includes insect larvae and tiny crustaceans.
Where Common Bullies Live
Common bullies are usually found on the main islands of New Zealand. You might also spot a few on Stewart Island and Great Barrier Island. Some groups of common bullies live in lakes that are completely cut off from the sea. These are called land-locked populations.
Scientists think these fish got into these lakes a long time ago. Natural events likely blocked off the rivers or streams they lived in from the ocean. In these land-locked places, common bullies are an important food source. They are eaten by bigger freshwater fish like eels and trout.
How Common Bullies Reproduce
During the summer, common bullies get ready to have babies. The female fish move closer to the edges of lakes and streams. They attach hundreds or even thousands of tiny eggs to the underside of hard surfaces. These surfaces can be rocks or logs at the bottom of the water.
After the eggs are laid, the male fish fertilizes them. He then guards the eggs to keep them safe. When the baby bullies hatch, they are very tiny. They float around in the water like tiny specks. At this stage, they are called planktonic larvae. They eat even tinier creatures called zooplankton.
As the young bullies grow, they move into deeper water. Once they reach about 18 mm long, they start living on the bottom. They become fully grown at around one year old. A new generation of common bullies usually appears every two years.
