Clownfish produce a sugary mucus to protect themselves from the stings of sea anemones they live in.

The secret is in the runny nose. Chemical changes in the mucus that coats the clownfish’s body can blunt the sting of its symbiotic sea anemone.

Researchers have long suspected that something special in the mucus of the clownfish, also known as the clownfish, protects it from the microscopic stingers of the sea anemone’s tentacles. But the exact mechanism remained a mystery, he said. karen burke da silva At Flinders University, Australia.

To investigate, she and her colleagues bred orange clownfish (Amphiprion percula) and bubble tip sea anemone (Entacmaea four colors) at the Institute. Some fish and sea anemones live in pairs, while others live separately. The researchers collected mucus samples from the fish at various times before and after they had adapted to the anemone, and then placed the mucus on a microscope slide and pressed it against the anemone’s tentacles.

Sea anemones sting by firing small coiled venomous harpoons explosively from their stinging cells called stinging cells. The researchers used a microscope to count and compare the number of stinging cells that fired during the mucus treatment. They found that mucus from a clownfish’s partner, but not mucus from an unknown fish, reduced the firing of stinging cells.

To find out why, the researchers analyzed how the glycans (chains of sugar attached to proteins) and fats in the clownfish’s mucus change as they adapt to their hosts. Three weeks after the symbiotic partnership began, the chemical profile of the mucus changed significantly. In particular, the concentrations of seven types of glycans were changed. Removing glycans or otherwise tweaking them could be one way he suppresses line cell firing, Burke da Silva says.

Alonso Delgado At Ohio State University, the sea anemone shrimp (Ansiromenes Magnificus), using similar glycan methods or evolving different strategies to thwart sting.

Additional strategies may also be at work for clownfish. Glycan changes are slow, and after a partner splits, he grows back within a day. Instead, fish may use an unknown chemical strategy at the very beginning to gain initial access to sea anemones.