Imagine a giant fish drifting slowly through the ocean. This is the sunfish, a truly amazing creature known for its unusual size and shape. It’s the largest bony fish in the world and can grow to be nearly ten feet long and up to 14 feet tall! Because of its shape, it looks like it’s only half a fish, which is why people sometimes call it “the swimming head.”
The sunfish has a very special shape. Its body is curved and looks like it was cut off at the back. This happens because its back fin doesn’t grow all the way. Instead, it folds into itself as the fish gets older, creating a rounded part called the clavis. The sunfish uses this clavis to help it move through the water.
The sunfish’s look inspired its Latin name, “mola,” which means millstone. This name fits because the sunfish is round like a millstone and has skin that feels like stone. Its rough skin often gets parasites, which are tiny creatures that live on it. This leads to some interesting behaviors in the ocean.
To get rid of these parasites, sunfish sometimes jump out of the water, leaping up to ten feet high and then splashing back down. This is similar to what some sharks and turtles do. Sunfish also have a special relationship with smaller fish and sea creatures that eat the parasites off their skin. This is called a symbiotic relationship because it helps both the sunfish and the smaller creatures.
Sunfish move slowly, so they eat things that drift in the ocean currents. Their diet includes jellyfish, plankton, and other small sea animals. They have small mouths that can’t close completely, which helps them eat these tiny creatures as they float by.
The sunfish is a wonderful example of how animals adapt and work together in the ocean. Its unique shape, behaviors, and eating habits show us the amazing relationships that exist in the sea. Learning about sunfish helps us appreciate the incredible variety of life under the waves.
Use clay or playdough to create your own model of a sunfish. Pay attention to its unique shape, especially the clavis. Once you’re done, explain to your classmates how the sunfish’s shape helps it move through the water.
Pair up with a classmate and role-play the symbiotic relationship between a sunfish and smaller sea creatures. One of you will be the sunfish, and the other will be the cleaner fish. Act out how the cleaner fish helps the sunfish by eating parasites off its skin.
Research the diet of the sunfish and create a poster that shows the different types of food it eats, such as jellyfish and plankton. Include drawings or pictures and explain why these foods are suitable for the sunfish’s small mouth.
Calculate the area of a sunfish’s body if it is approximately 10 feet long and 14 feet tall. Use the formula for the area of an ellipse: $$A = pi times frac{length}{2} times frac{height}{2}$$. Discuss how its large size might affect its behavior and interactions in the ocean.
Conduct an experiment to understand how sunfish jump out of the water to remove parasites. Use a small container of water and a toy fish. Try different ways to make the toy fish “jump” and splash back down. Discuss how this behavior helps the sunfish stay healthy.
Sunfish – A large, flat-bodied fish that lives in the ocean and is known for basking in the sun near the surface of the water. – The sunfish can often be seen floating on its side at the ocean’s surface, soaking up the sun’s rays.
Ocean – A vast body of saltwater that covers most of the Earth’s surface and is home to a wide variety of marine life. – The ocean is teeming with life, from tiny plankton to the massive blue whale.
Parasites – Organisms that live on or inside another organism (the host) and benefit by deriving nutrients at the host’s expense. – Some fish have parasites that attach to their skin and feed on their blood.
Symbiotic – A relationship between two different organisms where both benefit from each other. – Clownfish and sea anemones have a symbiotic relationship, where the clownfish gets protection and the anemone gets food scraps.
Diet – The kinds of food that an organism regularly eats to survive and grow. – The diet of a jellyfish mainly consists of small fish and plankton.
Jellyfish – A sea creature with a soft, jelly-like body and tentacles that can sting. – Jellyfish drift through the ocean currents, capturing prey with their stinging tentacles.
Plankton – Small and microscopic organisms that float or drift in water, serving as a crucial food source for many marine animals. – Whales feed on plankton by filtering large amounts of water through their baleen plates.
Behavior – The way an organism acts or responds to its environment or other organisms. – The migratory behavior of birds is influenced by changes in temperature and daylight.
Morphology – The study of the form and structure of organisms and their specific structural features. – The morphology of a fish can tell us a lot about its habitat and lifestyle.
Relationships – The interactions and connections between different organisms in an ecosystem. – The predator-prey relationships in an ecosystem help maintain balance and biodiversity.
