With a conical shell bearing distinct ridges, the Thick Topshell can be abundant on wave-exposed shores. It feeds on algal films, helping keep rocks free of heavy algal growth. Around Lihou, check the rocks in churning water at mid tide, where these topshells may cling in small groups, each shell showing unique banding patterns.

Slipper Limpets can form “chains” of individuals, each sticking to the one below. In some areas, they can become invasive, crowding out native bivalves. At Lihou, you might spot them on rocks or other shells, creating layered stacks.

This bristle worm burrows in silty sediments, aerating the seabed while recycling organic matter, playing a vital cog in the coastal ecosystem.

Lugworms recycle nutrients by swallowing sand and digesting organic material, leaving coiled casts on the sand. Their burrowing aerates the sediment, benefitting the ecosystem. Around Lihou, you might notice their tell-tale spirals on sandy patches at low tide.

These tunicates filter plankton and detritus through siphons, occasionally “squirting” water if touched at low tide. Sea Squirts are primitive chordates, more closely related to vertebrates than you might think at first glance. Around Lihou, look for them attached to rocks in shallow pools, sometimes forming small clusters of jelly-like bodies.

This anemone has a central disc and tentacles arranged like petals, earning the “daisy” nickname. Colours range from pale brown to greenish, sometimes with stripes or spots. Around Lihou, look for it in deeper pools or on sandy patches between rocks—its tentacles spread out like a small, flower-like creature underwater.

These crabs have spiny carapaces and frequently decorate themselves with algae or sponges for camouflage. They may form large gatherings before moulting, offering a dramatic sight for snorkelers who come across a cluster. Near Lihou’s rocky coast, you might find smaller individuals in deeper pools.

Chitons clamp themselves tightly to rocks, their eight shell plates forming a segmented “armour.” They graze on algae at night and can be easy to miss unless you check carefully under stones during low tide. On Lihou, look for them on wave-exposed rocks or tucked into rocky crevices, where they remain unnoticed by day.

Scallops have a classic fan-shaped shell and can swim by rapidly. Scallops have light-sensitive eyes along the shell edge. Their strong adductor muscle is highly regarded in seafood dishes. Though usually found in deeper water, off Lihou if you explore the lower tidal areas you might encounter a live scallop. You may also find the shells of dead scallops washed up on the beaches.

This small sea slug can incorporate chloroplasts from the algae it consumes, letting it photosynthesise to some degree—an unusual trait in the animal kingdom. Its flattened body and vivid colour make it stand out against darker seaweed. Around Lihou, search carefully in rockpools where green algae grow; if you spot a tiny splash of bright green, it could be the Green Elysia.

Flat Periwinkles graze on algae coating wrack fronds, helping to keep seaweeds clear of overgrowth. Their shell colours can vary widely, providing camouflage against the seaweed. Around Lihou, you might spot them in clusters on bladderwrack at low tide, where their bright shells stand out once the water recedes.

These anemones are commonly red, but variants can be greenish or brownish. Underwater, they extend a ring of short tentacles to catch plankton and small invertebrates, but on exposed rocks, they pull in the tentacles, forming a glossy blob. On Lihou, they are plentiful in many pools, adding splashes of colour to the grey rocks at low tide.

Pink Sea Fans are slow-growing soft corals with delicate, branching fans in shades of pale to deeper pink. Each branch supports tiny polyps that filter plankton from the currents. Around Lihou, these fans are uncommon in shallow zones, but you may encounter them on a very low tide.

With a red column bearing pale spots reminiscent of strawberry seeds, this anemone is closely related to the Beadlet Anemone but generally bigger. It uses sticky tentacles to capture small invertebrates passing by. On Lihou, careful tidepool study may reveal these striking anemones tucked away where wave action or shade provides some cover.

Appearing as a fine, lacy or net-like crust on kelp surfaces, each small zooid has tentacles for filtering plankton. Together, these zooids form a delicate “sheet” that can grow quickly in warmer months. Off Lihou, if you lift a kelp frond during a calm low tide, you may spot the thin, white lace of sea mat colonies coating its surface. You may also find this on kelp fronds washed on to Lihou’s beaches after a storm.

This soft coral forms pale creamy-white or orange finger-like lumps, each a colony of tiny polyps that retract when disturbed. It usually grows in deeper water but can show up on vertical rock faces exposed only at the lowest tides. Around Lihou, explorers at a very low tide could spot these unusual coral-like protrusions clinging to shaded, submerged walls.

The Dahlia Anemone features vivid patterns in reds, oranges, and whites, resembling dahlia flower petals when fully open. Its sticky tentacles can trap small crustaceans and other prey. On Lihou, a careful look in deeper rockpools at low tide might reveal these bright anemones attached to stable surfaces, waiting for the tide to return.

Snakelocks Anemones retain their “snaky” tentacles in or out of water, giving them a lively appearance at low tide. Their bright green tentacles often sport purple tips, hinting at symbiotic algae within the anemone’s tissues. On Lihou, finding one is straightforward: look in sunlit pools or clinging to rocks where there is plenty of light for the algae to thrive.

Named for its flattened shape and wrinkled surface, this sponge varies from greyish to purplish in colour. Like other sponges, it filters large volumes of water to extract plankton. Near Lihou, you might find it on vertical rock faces or in dim crevices at the lowest tides, forming lumpy patches that feel rubbery to the touch.

This sponge has a crumbly texture when out of water and can appear yellowish-green or whitish underwater. It grows in large patches, offering hiding spots for small crustaceans and worms. On Lihou’s rocky shore, you may find breadcrumb sponge under overhangs in deeper pools.

Cushion Stars have a plump, cushiony form with short, rounded arms, often displaying greenish, brownish, or orange hues. They feed on small organisms and films on rock surfaces, and can regenerate lost arms over time. On Lihou, look for them under loose stones or within weedy crevices at low tide, where their subtle colours may help them blend in.

Named for their ear-like flaps, sea hares graze on seaweeds and can produce a purple ink when disturbed. Sometimes they gather in groups, laying spaghetti-like egg masses on rocks or algae. Around Lihou, you might spot them in calm pools or among kelp fronds, their gentle movements disguised by the surrounding algae.

This nudibranch feeds on anemones, storing stinging cells in its finger-like projections (cerata) for defence. Its pale grey or off-white colour helps it blend in with rocks or shells. On Lihou, if you look closely among beadlet anemones in tidal pools, you might see one gliding slowly, leaving bare patches where it has consumed its prey.

Sea Lemons are nudibranchs, often yellow with darker blotches, feasting on sponges along rocky substrates. They lay distinctive coiled ribbons of eggs, which can be spotted attached to underwater surfaces. Around Lihou, if you carefully inspect shaded rock ledges in deeper pools, you may catch sight of one, slowly moving over sponges in search of its next meal.

Despite their name, sea spiders are not true spiders but share the arthropod phylum. They use a straw-like proboscis to feed on soft-bodied animals like anemones and bryozoans. Around Lihou, careful explorers might find them clinging to seaweed or sponges, but their spindly forms and small size make them easy to miss.

These small urchins graze on algae, helping to control seaweed overgrowth on rocks. They sometimes pick up shells or pebbles on their spines for extra camouflage. Around Lihou, you might glimpse them in deeper rockpools.

Brittle stars are more delicate than true starfish, relying on thin, flexible arms for quick, scuttling movement. If disturbed, they may lose an arm but can regenerate it over time. Around Lihou, look carefully under rocks or amongst kelp holdfasts in deeper pools to glimpse them crawling or clutching onto hidden surfaces.

This classic five-armed starfish uses tube feet to pry open mussels and barnacles, feasting on shellfish along the shore. On Lihou, low spring tides may reveal them clinging to rocks or shells just below the waterline. Their bright hues make them one of the most noticeable echinoderms in local coastal waters.

These isopods may appear greenish or brownish, blending in with the algae they graze on. By feeding on algae films and decaying material, they help keep the shore tidy. Near Lihou, you can spot them clinging to seaweed or creeping over rocks in rockpools, especially where the water remains relatively still.

Sea Slaters are quick-moving scavengers that feed on algae, decaying seaweed, and occasional dead animals. They can zip across rocks surprisingly fast when uncovered. Around Lihou’s intertidal zone, look under damp ledges or driftwood at mid-tide levels to discover these grey or mottled crustaceans.

Sea Scuds are translucent greenish or brownish crustaceans that scavenge on decaying plant material. They play an important role in recycling nutrients and also serve as food for small fish and shore birds. Around Lihou, look for them scuttling among seaweed fronds or rummaging in decomposing seaweed that accumulates in pools at low tide.

These tiny crustaceans jump energetically when disturbed, often found under rotting seaweed piles. They feed on decaying plant matter and help recycle nutrients along the coastline. On Lihou’s sandy patches, gently lift driftwood or seaweed at low tide to see them hop away in a flurry of miniature leaps.

Rock Barnacles occupy slightly higher zones on the shore than acorn barnacles, tolerating stronger waves and longer periods out of the water. From above, each barnacle has a more angular opening and clamps shut to retain moisture when exposed. On Lihou’s rocky ledges, you might find them in the splash zone above acorn barnacle bands, enduring wave action day after day.

Acorn Barnacles open their valves at high tide, extending feathery legs to filter plankton from the water. At low tide around Lihou, you will notice them clamped shut to conserve moisture, creating a fine crust on rocks or shells. Though small, these barnacles form important habitats for even smaller creatures that hide among their tight clusters.

Common Lobsters have a dark blueish or greenish shell and are heavily fished, so large individuals seldom appear in shallow areas. They prefer deeper waters but sometimes venture closer to Lihou’s rocky shores, particularly at night. If you do see one while exploring rockpools, keep a respectful distance—lobsters have powerful claws and are best admired without disturbing them.

Common Prawns are swift swimmers, often darting away if a rockpool is disturbed. Their translucent bodies show fine brownish or greenish patterns, making them well camouflaged among algae. Around Lihou, a careful observer may glimpse them feeding on detritus or picking at small organisms.

Despite the name, Squat Lobsters are more closely related to porcelain crabs and hermit crabs than to true lobsters. They have a flattened abdomen that they tuck beneath the thorax, and often show vibrant colours along their claws. Around Lihou, turning a rock in a deeper pool might reveal one, though they tend to scuttle backwards into a hidden gap if startled.

Porcelain Crabs are not “true crabs” but closely related, with flattened bodies and the ability to shed limbs if threatened, later regenerating them. They filter feed or pick up small bits of food with their small appendages. On Lihou, look carefully under stones during low tide to find them clinging upside down, ready to scurry away if disturbed.

Hermit Crabs have a soft abdomen and must occupy empty snail shells for protection, “upgrading” to larger shells as they grow. On Lihou, you can see them hiding among rocks – though they can be hard to spot as they can be mistaken for the shell that they occupy. Unlike many crabs, they do not have a fully protective carapace at the rear, making shells crucial for survival.

Velvet Swimming Crabs have bright red eyes and a velvety texture on their shell, which gives them their common name. They can be aggressive, raising their pincers and moving sideways at surprising speed if disturbed. Around Lihou, lift a rock or look in a kelp-covered pool at low tide and you may catch a glimpse of one, scuttling quickly to safety.

Known in Guernsey as Chancre, this crab has a brick-red shell with a pie-crust edging. It is a significant fishery species and can live for many years in deeper waters. Around Lihou, smaller individuals may wander into deeper rockpools, but large adults generally remain further offshore.

Typically greenish or brownish, the Shore Crab can change colour over time to match its surroundings and is quick to defend itself with pincers. It will eat anything it can handle, from worms and molluscs to bits of detritus. On Lihou, turning over a stone in a rockpool at low tide often reveals one scuttling away, claws raised in warning.

Common Cockles bury themselves just below the surface, filtering plankton and organic matter from the water. Their robust, ridged shells help protect them from predators like crabs and whelks. Around Lihou, they are more likely to inhabit sandy pockets or softer sediments at lower tide zones, where their siphons can reach the seawater. Look out for their empty shells washed up on the beaches – sometimes with the 2 parts still connected.

Ormers are a prized delicacy in the Channel Islands, where strict rules govern when and how they may be gathered to protect populations. They mark the northernmost natural range of Haliotis tuberculata worldwide. On Lihou, dedicated foragers must follow local guidelines, as unsustainable collecting can harm populations of these iconic abalones.

Blue Mussels attach themselves firmly using strong byssal threads. They filter seawater to feed on plankton. When the tide goes out, these mussels clamp shut, retaining moisture inside their shells until submerged again.

This attractive marine snail has a shell that can show hints of purple, green, or grey in a spiralled pattern. Around Lihou’s tidepools, it grazes on algal films, helping keep rock surfaces from becoming overgrown. If you gently turn stones at low tide, you may spot its distinctive whorl and sometimes a bright pink interior lip.

Common Whelks are larger than dog whelks and are often collected for food in traditional seafood dishes. They prefer softer sediments where they hunt worms and small invertebrates. Around Lihou, juveniles may sometimes be found in lower shore pools, while adults mostly remain in deeper waters, occasionally washing ashore after storms.

Dog Whelks drill neat holes into the shells of barnacles or mussels to reach the soft flesh inside. Their shell colour can range from white to brown, depending on local conditions. On Lihou, look out for them in areas where they are barnacles or mussels, where they leave behind tell-tale drilled shells as evidence of their meals.

A familiar snail on most rocky coasts, the periwinkle grazes on algae, helping keep surfaces from becoming overgrown. Around Lihou, large clusters can appear wherever seaweeds flourish, especially in sheltered rockpools. Its sturdy shell offers good protection from waves and predators like crabs.

Limpets scrape algae off rocks using a radula—an impressive, tooth-like structure. Each limpet often returns to its exact “home scar” in the rock, fitting perfectly to reduce water loss when exposed at low tide. On Lihou’s intertidal rocks, you will find these conical creatures, securely gripping even in wave-swept conditions.

A master of disguise, the Common Cuttlefish can flash moving patterns on its skin while hunting fish or crustaceans. Around Lihou, cuttlebones sometimes wash ashore after storms, revealing the unique internal shell.

Only about 3 cm mantle length, this bobtail squid hides by day in sandy or muddy shallows around Lihou. At night, it emerges to hunt small shrimps and worms, using quick colour changes for camouflage. Unlike true cuttlefish, it does not leave a prominent “cuttlebone” behind.