Colorful nudibranchs are sure to spice up any snorkeling or diving trip! Nudibranchs come in all sizes, ranging from less than an inch to 12 inches long. While over 3,000 species of nudibranchs are found throughout the world’s oceans, they reach their greatest abundance and diversity in shallow, tropical waters.
Nudibranchs belong to the class Gastropoda (snails and slugs), then the order Nudibranchia. They get their name from the feathery gills on their backs – nudus is Latin for “naked”, while branchia is Greek for “gills”.
Nudibranchs feed on algae, sponges, anemones, coral, hydroids, barnacles, and sometimes other nudibranchs as well. They find food using the club-shaped rhinophores found on their heads. These rhinophores detect chemicals (or “scents”) dissolved in the water.
How do these itty bitty creatures keep predators away? While their bright colors make them easy to spot, the same colors also warn potential predators that they don’t taste so good. If the predator ignores this warning, some species of nudibranchs have another line of defense. Nudibranchs that feed on hydroids can store the hydroid’s nematocysts (the stinging cells found in hydroids, jellyfish, and anemones) in special structures called cerata and use these stingers for their own protection. Pretty cool, huh?
Spot nudibranchs and other fun critters when you visit El Nido!