A tongue-eating parasite found inside a fish dish in south London has been hailed an "extraordinary find".
The louse burrows into fishes' mouths and eats their tongues
Lewisham Council were called in when a south London resident found the creature in the mouth of a red snapper being prepared for a meal at home.
Dr Jim Brock, keeper of natural history at the Horniman Museum, has now identified it as a tongue-eating isopod, a type of louse.
The louse burrows through fishes' gills and attaches itself to the tongue.
It survives by drinking blood from the artery which supplies the tongue, Dr Brock said.
Despite its feeding habits, the louse was described as being a "harmless natural phenomenon" by Councillor Andrew Brown, Lewisham's cabinet member for the environment.
The creature is believed to be the only one in the natural world which eats and replaces a host's organ.
Dr Brock said: "I have not seen this species in all my 13 years at the museum so it's a remarkable find.
"I suspect the tongue louse was either imported here in the mouth of the red snapper or perhaps it has started to breed in European seas."