The Sea Môr Aquarium is home to a variety of marine creatures, representing the diversity of life found in Welsh waters. Highlights include our moon jellyfish and rock pool adventure tank, where children can touch starfish, anemones and small crabs.

The aquarium allows close up views of the animals possibly only glimpsed in their natural environment. The guided tour, provided by Sea Trust marine biologists, is packed full of fun facts, creating an eye-opening experience for children and adults alike. The whole experience lasts around 45 mins. All children must be accompanied by a responsible adult.

The tour was very informative and interesting. [The guide] was brilliant, answering the kids questions simply and patiently, she even gave us tips on where to view seals and dolphins

Tracy C

Three-bearded Rockling

Brithyll Mair tair-barf

Gaidropsaurus vulgaris

Rocklings have long, sinuous bodies and at a quick glance, as they slither rapidly out of sight, could be mistaken for an eel. They are actually related to cod, and like cod, they have a chin barbel (or spike) as well as barbels on the head. The Three-bearded Rockling gets its name from the three barbels around its mouth. Rocklings have two dorsal fins, but the first one consists of a fringe of very short rays preceded by one longer ray. In our Rocky Shore tank, you can see our Three-bearded Rockling and its mesmerising fin which ripples along its back!

The Three-bearded Rockling is the largest found around the British Isles, growing up to 50 cm long, compared to the Northern Rockling which is just 15 cm long. They can live very deep in the sea, down to 150 m deep! In shallower water, they live amongst dense seaweed.

Fun Fact: Young rockling, known as ‘mackerel midge’ are metallic blue-green and are an important food item for tern and Puffin chicks!

Image result for puffin chick
Photo courtesy USFWS/Flickr

Conger Eel


Conger conger

The Conger eel is the largest eel found in Welsh waters and can reach 3 m long. Conger eels are nocturnal and stay in their hidey holes during the day. At night they emerge and swim freely, searching amongst the rocks and seaweeds for hidden crabs, fish, lobster, octopus and other bottom-dwelling animals.

A conger eel lives nearly its whole life an an immature fish. When it does finally mature, between 5-15 years old, it will spawn once and then die. They swim miles out into the deep Atlantic to their spawning grounds. The eggs hatch into a leaf-shaped ‘leptocephali’ larvae which drift back inshore over one to two years and metamorphose into young eels!

Leptocephali larvae

Moon Jellyfish


Aurelia aurita

Jellyfish have been around for 300 million years, which makes them older than the dinosaurs! The moon jellyfish that live off the coast of Pembrokeshire are found throughout most of the Atlantic, in water between 9 and 19 degrees Celsius, and can grow up to 40cm wide. They float on the tides, although they can swim, an eat plankton and molluscs by guiding them into their bodies with their tentacles. They don’t have brains, but do have a nervous system that is capable of detecting light, movement and changes in temperature. Watch out, though, because jellyfish sting if touched!


Yellow Bellied Terrapins

terrapin melyn melyn

Trachemys scripta scripta

Yellow bellied terrapins come from the south eastern USA, where they live in rivers, swamps, marshes and ponds. They eat crayfish, veg, fruit, snails, insects and tadpoles, amongst other things. They grow up to about 20cm long and can live for up to 25 years. They mate in spring, laying eggs in nests on land that incubate and then hatch after three months. The young wait in the nest until the following spring when they go into the water. They live most of their life in the water, coming out onto land only occasionally.

They are very popular pets, particularly after the Teenage Mutant Ninja Turtle films, but often get dumped in the wild once they grow big or once people realise how long they live. In the wild they can cause havoc in the local area, and have become a real problem. Our terrapins, Rachel and Michelle, were similar outcasts, given to us once their owners realised they had grown too big for their tank.

Hermit Crab

cranc teimlad

Dardanus calidus

There are lots of different varieties of hermit crab. They can live up to 30 years, grow up to the size of a coconut and live on the sandy bottom of the sea where they can burrow. They have a spiral shaped body and live in borrowed shells, swapping for a bigger shell when they outgrow their current home. They have five sets of legs – the first pair are adapted into claws, it walks on the middle two pairs, and the back two pairs hold onto the shell.

Fun fact! They live in groups and have been known to form a vacancy chain where they all line up in size order and then all swap up to the next shell in quick succession as shells are increasingly rare (humans are to blame!) and highly prized. Some of them also live in a symbiotic relationship with a sea anemone which lives on its shell, offering leftovers in exchange for protection.


Thin lipped Grey Mullet

mwled llwyd wedi’i thaplu

Chelon ramada

Thin lipped Grey Mullet are common in Europe, and increasingly common in UK waters, spreading from the south and west up into northern waters. They grow normally to about 35cm long and eat detritus by scooping up mouthfuls of water or seabed in their mouths, filtering out the inedible bits through their gills. They live in still calm waters, such as marinas, harbours and are easily spooked, making them very difficult to catch. Fishermen often wear very neutral coloured clothing when trying to catch mullet. They grow very slowly which means that potentially they are susceptible to overfishing.

Fun fact!  They have been eaten by people since Roman times.