"Sea urchins are found in sandy spots near rocks and coral, often in popular snorkelling areas. They are generally spotted easily - look for dark spheres radiating thin spines. In such environments, take care, when wading or snorkelling, not to be knocked over by waves and tidal surges. Contact with sea urchins may leave their spines embedded in your skin. The larger ones can sometimes be removed with tweezers. Where spines are too fine to be plucked out, the preferred local method is to break them up using a blunt instrument such as a smooth stone or knife handle. Once the spines have been dealt with, the painful venom can be neutralised by immersing the affected area in very hot water for 30-90 minutes.
"Scorpionfish, lionfish and zebrafish all look very colourful and interesting, but their dorsal spines can pack a painful wallop - don't touch! It's very unlikely that you will be stung by one of these bizarre beauties, but if so, use the hot-water treatment described for sea urchins.
"Cone shells are cone-shaped sea-snails with a venomous proboscis that darts from the narrow end of the shell to ward off aggressors. The pain of their sting can be intense, and venom doses are sometimes fatal. Never touch or even get close to a cone-shaped shell in the sea."
`Thailand's Islands and Beaches' is published this month by Lonely Planet, price pounds 9.99.Reuse content