A podgy piranha has developed a weight problem because he feasts on fruit, instead of flesh.
The 2ft fish, called Peter, would strike fear into other animals in its natural Amazonian habitat.
He and his friends are capable of stripping the flesh from a body in a matter of seconds.
But, in his tank at a fire station in Sunderland, Peter is getting fat and lazy.
He turns up his nose at chicken morsels and will only eat grapes, bananas and apple chunks.
The diet has resulted in him ballooning beyond his natural size, to the point where he is too big for his 7ft tank.
Firefighter Scott Lumsden bought Peter, and took him to Rainton Bridge fire station as his crew's mascot.
Now, they are looking for someone who can take portly Peter of their hands, and give him a new home.
Mr Lumsden said: "We sometimes feed him by hand, but you have to watch your fingers in case he has a go. He will eat chicken and meat if he has to, but he has come to prefer fruit.
"Most ordinary people believe all piranhas can strip the flesh of a human body in seconds, leaving only a skeleton behind, and won't entertain such a creature in their homes.
"Our Peter isn't like that. He's a vegetarian piranha, but I am worried that if he grows any bigger he'll get stressed out and turn nasty with frustration.
"He was only the size of a finger nail when he arrived two years ago, but now he's outgrown his tank.
"We'll keep him if we have to, but it's not really fair, because he can't swim about any more."
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