Coral reefs are often referred to as the rainforests of the sea, primarily because of their incredible species diversity. Large apex predators like shark and barracuda are ever present on many reefs, stalking schools of brightly colored tropical fishes among sea turtles and other creatures that come to the reef for rest, shelter, food, and even a little spritzing up at a cleaning station.
But perhaps the most fascinating lifeforms are the tiny species of coral reefs, who may live out their entire lives undetected by observers — human or otherwise. Let’s take a look at just seven of these diminutive denizens of coral reefs.
Blenny
Blennies are some of the more common tiny species of coral reefs, with roughly 833 species across 130 genera. Their elongated bodies measure from just 1-5 inches in length, and they often inhabit crevices within corals, abandoned shells, or burrow into the sandy substrate.
Nudibranch
Colloquially referred to as sea slugs, nudibranchs come in a wide variety of shapes, colors, textures, and sizes, but most only grow to a few millimeters to an inch in length — about the size of a pinky fingernail!
Seahorse
While some species of seahorse can grow up to 14 inches in length, many species fall within a range of half inch to a couple inches. The smallest of the seahorse family is the pygmy seahorse, which measures 15mm and less!
Christmas Tree Worm
The Christmas tree worm is one of the more charming tiny species of coral reefs, as the spiral of feathery tentacles it extends to feed call to mind the conical shape of a Christmas tree. These creatures are often found in groups on coral heads, measuring just a few inches across.
Harlequin Shrimp
Harlequin shrimp may be tiny at just a couple inches in length when fully mature, but that doesn’t stop these killing machines from taking down starfish more than 10 times their size, often keeping them alive as they feed so the meat stays fresh.
Cowry
The cowry ranges in length from 5mm to 7 inches, and is often found along the lower reaches of the reef or on the substrate. Their shells are some of the most prized in multiple cultures across the globe, even serving as currency in some parts of the world.
Blue-Ringed Octopus
Many people are deathly afraid of the octopus, conjuring images of a giant, tentacled beast that can swallow them whole, but an octopus doesn’t need to be big to kill you. The blue-ringed octopus measures just 5-8 inches in length, but can deliver a dose of tetrodotoxin powerful enough to kill an adult human if provoked — so no touching!
