Found in the Mediterranean Sea and parts of the Atlantic, the Rainbow Sea Slug is a one of the most strikingly colorful animals in the ocean! Those colors aren’t just for show — like many nudibranchs, it steals stinging cells from the hydroids it feeds on and stores them in its cerata as a defense against predators!

​

It has also been increasingly spotted further north along UK coastlines in recent years, believed to be a result of warming sea surface temperatures  — making it an unexpected but vivid indicator of ocean change.