The weever fish... a spiky little character out to ruin your day
People taking advantage of the heatwave to head to the beach are being warned of a threat from an unusual source - a venomous fish.
There have been reports of bathers feeling the sharp end of weever fish, which can deliver an excruciating sting.
RNLI lifeguard Beth Montgomery, who works at Portstewart Strand, said that the fish were a growing problem for people enjoying a dip: "You can't see them, but if you stand on one it can cause immense stinging pain.
"Then we have to administer intensive first aid."
The weever is a small poisonous fish that is found under the sand on Irish coasts. It usually lives beyond the tide line, but when waters are low people are likely to walk into its territory.
The fish is brown, about 15cm long, and has black venomous spines along its dorsal fin.
Experts stress that it is rare to get stung.
But people are advised not to swim until at least an hour after low water.
It is simplest to wear some form of footwear in the water and to shuffle your feet through the sand as you walk - this disturbance should scare away any nearby fish.
If you do get stung, plunge your feet into very hot water.
In some extreme cases, you may need an anti-venom injection.