For many people, Easter means an abundance of chocolate eggs and fun hunting in which to find them. From gigantic chocolate ones to brightly-painted decorative ones, people everywhere carefully place their eggs beneath bushes and plants to hide them away until the time is right, and the same is true even of a unique species of fish deep in the heart of South America.

Known colloquially as the “splashing tetra”, Copella arnoldi seems at first glance to be nothing more than a small, rather dull-looking fish with no particularly remarkable distinguishing features to speak of. Its feeding habits are similarly quite ordinary as it prefers live foods such as insect larvae and Daphnia, and it’s only really when it’s time to breed that the little fish does something truly amazing.

As far as scientists around the world have been able to show, C. arnoldi is completely unique in that it is the only fish to lay its eggs on plants outside the water. After attracting a mate with an enticing display, the male of the species will physically leap out of the water with the female and both will attach themselves to the underside of an overhanging leaf with fin suction. The female will then lay 6 to 8 eggs on the leaf while the male fertilises them, and both will then drop off and splash back down into the water. While the process is over in a matter of seconds, the couple will repeat the acrobatics over and over again until they’ve deposited over 200 eggs on the leaf.

Even then, the work isn’t over - the male will stay around to periodically splash water up onto the eggs with his tail to prevent them from drying out and when the tiny fry are ready to hatch, they wriggle free of their eggs and plop down into the water below and swim for cover. This remarkable display of parenting has never been seen anywhere else and it offers a clear benefit in keeping the vulnerable fry out of the reach of any aquatic predators. So while these wonderful fish are hiding their eggs for safety rather than fun, it’d nice to know that some Easter traditions are shared by a small but amazing fish in the heart of the Amazon.

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