Juvenile Hermit Crabs are common on rocky shores in all months of the year and there were many reports of these fascinating crustaceans in January 1997 when on many shores the fauna was exceptionally sparse. Of the 15 or so species recorded regularly in British seas, the species known as the Common Hermit Crab , Pagurus bernhardus, is by far the commonest. If the major claw is on the right side, nearest the apex, you can almost certainly assume that a Hermit Crab found between the tides is this species. Squabbles Continual fights and squabbles are the result of keeping several Hermit Crabs in the same aquarium. This can be explained by the need for the crab to protect its soft abdomen with a borrowed shell. .
Fights occur when the crabs dispute the available shells.
In the Common Hermit Crab the eggs hatch into larvae in the first two months of the year. At this hazardous stage they will undergo moults like all crustaceans. The first planktonic stages are called zoea. Hermit Crabs are widespread on different demersal habitats, and the choice of shell depends on what is available. Pheasant Shells, Tricolia pullus , and Little Netted Dogwhelk Shells, Hinia incrassata , are a popular early choice on mid-Sussex shores.