It looks very much like our Giant reef worm (Eunice aphroditois) which can be commonly sighted on our reefs.
Our Giant reef worms are harmless to people. Like many marine creatures, they will not hurt you if you leave them alone. Those I've seen were mostly very nervous, sneaking out of their hiding places only to snatch mouthfuls of seaweed. Probably the poor worm that was in the aquarium was just very hungry and ate whatever it could.
Giant sea worm that attacked coral reef caught by aquarium staff
The Telegraph 19 Mar 09;
A 'giant sea worm' that has been has been attacking a coral reef and prize fish at The Blue Reef Aquarium in Newquay has finally been caught by staff working there.
Aquarists had been puzzled for months by violent attacks on their fragile reefs where the corals had been ripped in half.
After staking out the display for several weeks, the last resort was to completely dismantle it, rock by rock. Halfway through the process the predator was revealed as a four-foot reef worm.
Staff eventually lured it out with fish scraps but not before it bit through 20lb fishing line.
Matt Slater, the curator of the Cornwall attraction, said: "Something was guzzling our reef but we had no idea what, we also found an injured Tang Fish so we laid traps but they got ripped apart in the night.
"That worm must have obliterated the traps. The bait was full of hooks which he must have just digested."
"It really does look like something out of a horror movie. It's over four feet long with these bizarre-looking jaws. We also discovered that he is covered with thousands of bristles which are capable of inflicting a sting resulting in permanent numbness."
After being carefully removed the worm, which has been nicknamed 'Barry' by staff, was re-located into its own tank, safely away from the coral.
Giant Sea Worm Unmasked as Coral Killer
The Seoul Times 21 Mar 09;
A gigantic worm turned up at an aquarium in England, according to a tourist website of Great Britain. The 1.2 meter-long unidentified worm kills corals in the Blue Reef Aquarium.
The following is the rest of the story reported on March 17, 2009 from Newquay.
Aquarists at the Blue Reef Aquarium in Newquay have discovered the identity of a mysterious killer that had been devastating their coral reef display over recent months.
Staff at the award-winning attraction had been puzzled by violent attacks on their fragile living reefs - in some cases the corals had been literally cut in half.
After staking out the display for several weeks, aquarists decided as a last resort to take it apart rock by rock.
Halfway through the process the terrifying perpetrator was finally revealed - a monstrous four-foot-long giant reef worm.
Staff eventually lured it out with fish scraps - but not before it bit through 20lb fishing line.
Curator Matt Slater said: "As part of our tropical marine displays we have been painstakingly propagating a variety of corals. They are extremely slow-growing and every one we have lost to these attacks was a major blow.
"In the end it got so bad that I decided to literally take the display apart to find out who was responsible. I could hardly believe my eyes when I finally caught sight of the culprit.
"It really does look like something out of a horror movie! It's over four feet long with these bizarre-looking jaws. Having done some research we also discovered that it is covered with thousands of bristles which are capable of inflicting a sting resulting in permanent numbness."
Matt believes it probably arrived as a juvenile in a delivery of living rock from another aquarium.