Rock Pool Life

Elongated body with a large, blunt head and big eyes. Variable in color, often brown or beige with darker blotches. Males are almost black during the breeding season.

Found in rock pools and shallow waters, often hiding under stones or seaweed.

Eats a variety of food, including seaweed, barnacles, and small invertebrates

Common Gobies are small fish with a sandy grey colouration and darker patches blotching their back and sides. Their eyes are large and sit high up on their heads. This is the one you are most likely to catch or see.

The Common Goby is a small goby growing up to 6 cm in length. The top of the head, nape and throat are scaleless. It is grey or sandy in colour, often with darker blotches across the back and faint marks along the side of the body. There is also a dark area at the base of the pectoral fins and tail fin.

The Worm Pipefish (Nerophis lumbriciformis) is the most common pipefish found on UK shores. They are long, slender fish that looks like a worm or a piece of seaweed. They can get to 15cm in length, have a small dorsal fin behind the head and are dark green in colour. If you look closely at their head, you’ll notice a small snout similar to a seahorse.

The butterfish is a small eel-like fish found in rockpools and shallow seas all around the UK. They are pretty shy and are normally hidden in crevices or under rocks and seaweed. You might also hear of butterfish being called Gunnels or Rock Gunnels. They feed on anything they can find, including small crustaceans, molluscs and fish eggs. Butterfish lay their eggs on rocky shores, hiding them away from predators in crevices. Unlike in most fish species, both the Mum and the Dad take it in turn to guard their unhatched eggs from hungry predators.

Long spined sea scorpion has a large, bulbous head with a distinctive small barbel in each corner of the mouth. The body tapers down towards the tail, with large pectoral fins which sit behind the head. Colouration is usually mottled with pink, red and sandy blotches. This this species can adapt and blend in perfectly with the surrounding algae and encrusting organisms. Grows up to 20cm.

This colourful fish gets its name from the long spines attached to various parts of its body. This fish has amazing mottled colouration and can change its colouration to blend in perfectly with its background. A top predator it gulps up crabs and fish with its huge mouth.

The shore crab is the most common crab encountered on our shores. Normally a green-ish colour, shore crabs are easily found in rockpools or on the end of crab lines dangled into shallow waters.

Also known as the Green Shore Crab.

The edible crab is a large crab, brown in colour apart from black tips on the end of its claws. It is sometimes known as the brown crab. They have a thick, oval shaped shell (carapace) with a distinctive pie crust edge. Small juvenile individuals may be found in the rock pools.

They live on the lower shore and out under the sea to about 100m depth. On rocky shores, they are normally hidden away under boulders. It is an active predator and will feast on mussels, whelks and even smaller crabs. They are also known to dig for prey such as razor clams and otter shells.

Their body is covered in short hairs that give a velvet appearance and are soft to the touch, just like velvet. Like all swimming crabs, their rear-most legs are flattened like paddles, helping them swim effectively. They are speedy underwater and will catch swimming prey like fish and prawns, as well as munching on easier catches like worms, clams and sea snails.

If you spot a crab with a big orange mass on their underside, don’t worry – those are their eggs! Females carry the fertilised eggs around with them, protecting the eggs from hungry predators. An egg-carrying female is referred to as “berried”. 

A pear-shaped crab with a pointed face, the great spider crab has long, spindly legs like a spider. Also known as the sea toad, it lives amongst rocks and seaweed from the low tide mark and out to around 50m deep. It is a Northern species, with the UK sitting at the southernmost limit of its range. It is known to be partial to munching on jellyfish.

Spider crabs are very different to ‘typical’ crabs. Orangey brown in colour, the great spider crab has long spindly legs like a spider and a distinctive pear-shaped shell. It is smaller than the spiny spider crab, which has an oval and more visibly spiky shell.

The hermit crab will crawl around with the shell on its back and will only leave when it grows too big, and has to find a new, larger shell, such as that of the common whelk. In most cases, they will use the shells of dead snails, but squabbles for possession of an already occupied shell frequently occur. In addition to finding a new ‘home’, hermit crabs also moult. When ready to moult, the new skeleton grows under the old one. The old exo-skeleton splits and comes off; the new skeleton takes some time to harden.

One of the most fascinating aspects of hermit crab behaviour is their association with other animals. Acorn barnacles, or algae can be found growing on their shells and they can enjoy symbiotic (mutually beneficial) relationships with sea anemones. The anemones’ stinging tentacles help to deter predators and provide amazing camouflage. In return, the sea anemone gets scraps from the Hermit Crab’s meals and is transported to food sources. Some hermit crabs even transfer their anemones when they ‘move’ from a smaller shell into a larger shell. Like all British crab species the hermit crab is a scavenger and will look for dead and dying forms of marine life to feed on.

Despite their name, squat lobsters are actually small crabs belonging to the Galatheidae family. They are more closely related to porcelain and hermit crabs than true lobsters. 

Common prawns are found in rockpools and shallow waters down to around 40m deep, normally hiding in crevices or under stones. It is virtually identical to the Rockpool Shrimp (Palaemon elegans); they can be told apart by the number of teeth on the rostrum.Common prawns are scavengers and will eat anything they find, from decaying seaweed to dead mussels.

Both have a translucent body with brownish-red tiger stripes along the length. It has large eyes separated by a serrated rostrum. Its walking legs are banded with reddish-brown and bright yellow and it has very long brown antennae.

Common brittlestar: Ophiothrix fragilis

The common brittle star is extremely variable in colouration, ranging from violet, purple or red to yellowish or pale grey, often spotted with red. The arms are usually white or grey with pink bands. The central disc is about one centimetre in diameter with the five arms being about five times as long. The disc is clothed in five rays of spines radiating from a spiny centre. Between these are five pairs of triangular plates, each pair forming a heart shaped pattern. The slender tapering arms are quite distinct from the disc and are covered with overlapping scales.The dorsal arm plates are naked and have a longitudinal keel. Each arm segment bears seven glassy, toothed spines. The arms are extremely fragile and easily shed, coming away either whole or in pieces.