Researchers discovered that bacteria living on frog skin can protect against a dangerous water mold called Saprolegnia that kills amphibian eggs and young tadpoles. They tested 196 different bacteria from frogs in Portugal and found that certain bacteria, especially Bacillus species, could stop the mold from growing. Interestingly, these bacteria worked best in clean water environments with fewer nutrients, similar to natural pond conditions, suggesting nature has built-in protections for amphibians.