Gerald, a pet goldfish, looks like a normal standard-sized pet fish when his owner won him at a carnival 2 years ago in July.

But she soon discovered that Gerald was a wild animal.

Gerald is now 12 inches massive, which means he outgrew his 2 tank mates.

The massive size of the pet goldfish forced Alexandria Miller, the owner of Gerald, to buy a tank that is worth $1,300 for the fish.

In case you’re wondering why Alexandria had to buy a new tank for Gerald, it is because this goldfish ended up eating his fellow tank mates.

This forced Alexandria to isolate him from the other fishes.

Alexandria, who is from Chicago, USA, said Gerald is very food motivated.

She explained: “When I first got him, he was in a plastic bag and was just under two inches.”

She added, “He just looked like your regular goldfish and I thought they grew to their environment so I was expecting him to just stop growing but within a month of me having him he was already getting bigger.”

She continued, “He does lay around a lot but it seems when he’s bored or hungry, he jumps out of the water and likes to grabs the thermometer inside his tank. He’ll click it against the glass till he’s got our attention – he’s food motivated but can be calm until he’s hungry. Then he seems to get grumpy towards me – but if I put a smaller fish in there with him, he will eat them, which he has done several times.”

Because Gerald is still in his younger years, Alexandria is already on the lookout to find new bigger tanks for him.

Normal types of goldfish can only grow to up to 1 or 2 inches long, but wild goldfish, which is the type of goldfish Gerald is, are capable of growing to up to 12 to 14 inches long.

Alexandria said, “He’s so hard to measure – even when we were putting him in his new tank, my friend commented on how much bigger he looks in the flesh.”

Alexandria added, “I can’t hold the tape measure next to him, and after moving him into the big tank he won’t even let me touch him. I’ve been luring him to the glass with food to try and get his size.”

She added, “We think he’s about two years old but we’ve got no way of knowing for sure – and some people think he’s stopped growing but I’m not convinced.”

Any advice for Alexandria?