A new study has found a parasite living inside fish eyeball controls its behaviour. When the parasite is young, it helps its host stay safe from predators. But once the parasite matures, it does everything it can to get that fish eaten by a bird and so continue its life cycle.

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A new study has found a parasite living inside fish eyeball controls its behaviour. When the parasite is young, it helps its host stay safe from predators. But once the parasite matures, it does everything it can to get that fish eaten by a bird and so continue its life cycle.