A FISH-KILLING worm has been caught by Environment Agency Wales officers.

The nematode has a devastating effect on its prey, growing inside them then bursting through their bodies like the creature in the movie Alien.

The worm was found during a routine fish health check.

Philometroides sanguinea infects carp and goldfish.

An Environment Agency spokesman said, "It kills them by burrowing through their gut wall then maturing quickly in their bodies."

The discovery in Wales is only the second time the worm has been found in British waters.

It has sparked major concerns for the health of carp in Welsh waters, numbers of which are already declining.

It could also affect expensive goldfish in garden ponds, garden centres and pet shops.

Nigel Hewlett, senior fisheries scientist in Wales, described the discovery as "very worrying".