The western mosquitofish (Gambusia affinis) stands out in polluted waters. It often thrives where other fish cannot. Why does this happen?  This question has been explored in a recent study.

    Scientists looked at how different fish handle selenium. Selenium is a tricky element. It can be useful in small amounts. But too much can be harmful. The study focused on selenomethionine (Se-Met), a form of selenium. It checked how eight fish species reacted to it. Four of these fish lay eggs. The other four carry their young inside them until they are born.

    The western mosquitofish showed the highest tolerance to Se-Met. This means it can handle more selenium than the other fish. The study also looked at how selenium affects the fish's genes. It found that the genes related to selenoproteins and sulfoproteins reacted differently in the western mosquitofish and zebrafish. Selenoproteins are proteins that contain selenium. They play a big role in how the body handles selenium.

    The study also looked at the long-term effects of selenium on the fish. It found that selenium levels in the reproductive organs, the development of these organs, and the early stages of life differed between the western mosquitofish and the zebrafish. The western mosquitofish also showed a greater ability to remove selenium from their bodies. This is especially true for their offspring.

    The genes related to antioxidants and inflammation were also studied. These genes were more active in the western mosquitofish. But they were less active in the zebrafish. Antioxidants help protect the body from damage. Inflammation is the body's response to injury or infection.

    So, what does this all mean? The western mosquitofish's ability to handle selenium and its active antioxidant genes might explain why it can survive in selenium-contaminated waters. This is important to know. It can help in understanding how to protect our waterways. It can also help in preserving the fish that live in them.

The Secret of the Hardy Mosquitofish

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