Man finds tongue eating parasite as he tucks in to Morrisons sea bass dinnerÂ Paul Poli bought a fillet of sea bass for his dinner from the supermarketÂ Asked for an un-filleted fish from the fishmonger's counter in the storeÂ Was about to tuck into it when he discovered a yellow creature inside itÂ Louse was identified as a cymothoa exigua, a tongue-eating parasiteÂ Â Morrisons said parasites may be present in un-filleted fish in rareÂ occasions Presented Mr Poli with a Â£20 gift voucher and a bottle of wine to apologise A retired headmaster who bought sea bass from Morrisons found a 3cm long tongue eating parasite in the fish just as he sat down to eat it. Paul Poli, 62, was about to tuck into his dinner when he spotted the gruesome yellow creature inside the fish. He took it back to the Morrisons supermarket in Llanelli, where he had bought the sea bass from the fishmonger's counter. The 3cm tongue-eating parasite, which was found in a fillet of sea bass a shopper bought at his local Morrisons supermarketÂ He had asked for an un-filleted fish rather than one that had already been pre-packed. The parasite was then idenitified as cymothoa exigua, which is more commonly known as the tongue eating louse. The parasite enters the fish through its gills, attaches itself to its tongue and then eats its. Staff at the Morrison's fish counter identified the parasite as a cymothoa exigua, which is more commonly known as the tongue-eating louse (file picture) Â The Morrisons store in Llanelli, South Wales, pictured, has since apologised to Mr Poli and has given him a Â£20 gift voucher and a bottle of wineÂ They aren't usually harmful to humans, although if they are alive, they can bite. Cymothoa Exigua is more commonly known as the tongue-eating louse and is a parasite, which attaches itself to the tongue of a fish. It enters the fish through its gills before attaching itself to the tongue. It then replaces the tongue and feeds on the blood of the fish as well as any other food that it takes in. The parasite can bite humans but is not thought to be harmful to them in any other way. Mr Poli, of Llanon, South Wales said: 'It was disgusting - I love fish but it's put me off it for life now. It was about 3cm long and 8mm wide - luckily just big enough for me to see before I put it in my mouth. Morrisons apologised to Mr Poli and have since given him a Â£20 voucher and a bottle of wine. A spokesman for the retailer said: 'Some fish often pick up parasites naturally from their eco system. Although we make every effort to screen these out during the skinning or packaging processes, they may be present on very rare occasions. 'Our skilled fishmongers will also identify them as they fillet a fish - Mr Poli's fish was sold un-filleted at his request.'