Staff at the Blue Planet Aquarium in Cheshire were unaware that a Sand sole (Pegusa lascaris) had been calling the place home for 15 years.
The bottom dweller, now named Nemo, was discovered when the 40,000 l. open native rockpool tank was undergoing routine cleaning. The fish was thought to have stowed away when the tank was delivered in 1996, as there were no records of the flatfish ever having arrived otherwise.
According to acting curator Colin Grist "We’ve called him Nemo, because we’ve found him, just like in the film - except we didn’t know we were looking. Although we haven't been aware of its existence it seems to have been doing extremely well. It's in perfect condition and has obviously been feeding well and probably waiting until the lights go out to go hunting."
"It's extraordinary that it's managed to have remained hidden for so long but it does go to show just how well evolved it is to its natural environment," he added.
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