Weevers are back on our beaches for the summer season and posing a painful risk to unsuspecting bathers.
The fish have tiny venomous spines on their dorsal fins, which can deliver an excruciating sting to anyone who stands on one.
East Riding of Yorkshire Council said it was in the process of putting up warning signs in resorts and urged people to "not walk barefoot on the sands during the weever fish season" in the summer months.
Rosie Bullard, who runs a first aid station in Hornsea, said the best cure for a sting was to immerse the affected area in water "as hot as you can bear it" in order to "cook" the protein in the venom.
Described as "naff swimmers" by the British Marine Life Study Society, weevers spend most of their time on the sea floor.
It means beachgoers wiggling their bare toes in the sand may find the feeling goes from ecstasy to agony.
The easiest remedy is to wear waterproof shoes, but Ms Bullard treats about two children each week for stings suffered while paddling.
She advised washing the wound before removing the sting with tweezer or the edge of a credit card and then soaking it in hot water.
The advice is shared by the NHS, which recommends using salt water, rather than fresh water to rinse the wound, and soaking in hot water for at least 30 minutes while taking care not to scald.
Helen Stubbs, who lives in nearby Aldbrough, said she remembered the excruciating pain when she was stung as a child after forgetting her jelly shoes.
"I've never been stung by a wasp, but people say it's like that but tenfold at least," she added. "They've always been prolific on this coast, but people aren't aware of them."
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