Goldfish are iconic pets. These brightly colored fish are known for being hardy and relatively easy to care for.

When most people think of goldfish, they probably imagine a relatively unremarkable orange fish that’s an inch or two long, but that’s not always the case.

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“Goldfish are actually a type of domesticated carp,” writes Carrie Arnold for National Geographic.

“Almost 2,000 years ago, the ancient Chinese began to domesticate Prussian carp, Carassius gibelio, for food and as ornamental fish.”

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Carp are relatively large fish—definitely too big for most home aquariums. And, it turns out, it’s not necessarily all that uncommon for goldfish to grow as large as their ancestors.

Reddit user TobiDaDog shared pictures of a pair of particularly large goldfish.

“So a few years ago my mom decided to surprise my dad by putting a couple of Walmart goldfish in his large pond,” the Redditor and goldfish enthusiast wrote on an Aquariums subreddit.

“She forgot about them,” the story continued. “He never saw them until he drained it for maintenance [a couple of weeks ago]. Surprise!”

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When another Redditor asked about what happened to these two monster goldfish, u/TobiDaDog explained that the fish “got put back! This was a man made pond, by the way. No where near any other water source.”

Goldfish are technically an invasive species that can damage ecosystems. It’s good to know these two are just ornamental.

These aren’t the first surprisingly large goldfish to be discovered, though.

Big Bob became a minor celebrity in late 2015 when his human, Anne Cooper, realized that the fish was as large as a Subway sandwich.

The fish “is more than a foot in length and shows no signs of stopping,” Cooper told the Daily Mail. “His size is quite intimidating to the cats who often approach him but if he moves suddenly then they run away in fright.”

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Daily Mail

Cooper says that Bob’s fish tank is five feet long—probably around 100 gallons—and that she may need to find an even larger tank to accommodate the ever-growing goldfish. A new tank would make for Big Bob’s fifth residence within Cooper’s home.

“He seems quite intelligent, he knows when his feeding time is and he knows what food he wants. He also has a bad temper when he doesn’t get what he wants and often gets quite angry!”

Not wanting to wait for lunch is not the only reason Big Bob acts out; he also hates the color red.

“On one occasion my son Anthony left a packet of Skittles on the side by the tank and Bob went crazy, dashing up and down, splashing water everywhere and even bashing his head into the glass. …He must think it’s a rival,” Cooper hypothesized. “I have a violent goldfish!’

Goldfish can potentially be lifelong pets.

Some records show that the oldest common goldfish lived to be an impressive 43 years of age. Guinness World Records recognized the longest goldfish back in 2003, measuring 18.7 inches.

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If you find yourself raising a goldfish, make sure the fishy has enough space (bigger than a bowl, please), keep oxygen circulating in the water, feed it a high-protein diet, and keep the water temperature relatively warm and you may find yourself with an impressive, ever-growing pet of your own.