He eats more than 25 fish a day and weighs more than both his parents combined.
Pesto the king penguin's huge size and fluffy feathers have made him arguably the most famous penguin in Melbourne, drawing in visitors to SEALIFE and countless fans online.
But the nine-month-old penguin's body is about to change dramatically, his handler Jacinta Early told SBS News.
"He will actually lose all this weight pretty shortly. So what he does is go through his fledging, lose all that cute little brown fluff, and then he'll get that sleek coat.
Pesto is a huge king penguin chick who weighs as much as both his parents combined. Credit: Sea Life Melbourne
How did Pesto get so big?
He currently weighs 23 kilograms, much more than the average king penguin his age.
But he wasn't born big.
His birth weight was actually just under 200 grams, so his egg wasn't abnormally large.
His size is due to a mix of nature and nurture — Pesto loves to eat.
"Pesto easily gets four feeds a day and he eats anywhere from 25-32 fishes in a day. It's just like having healthy baby fat. We have no concerns in regards to his life expectancy with his size", Early said.
Like most of the penguins at SEALIFE, his favourite food is rainbow trout, a freshwater fish they wouldn't normally eat in the wild.
His biological dad Blake is the tallest penguin at the aquarium, explaining Pesto's height.
Pesto (right) has become arguably Australia's most famous penguin. Source: Supplied / Pranjali Sehgal
Tango and Hudson's eggs failed this year and at 22 years of age Blake was old enough to have earned a break, SEALIFE decided.
"They're incredible parents, he wouldn't have gotten this big and be this healthy and beautiful if it wasn't for the love and adoration of Tango and Hudson," Early said.
Fake news spread that Pesto's mother's name is Basil — a key ingredient of pesto sauce — but SEALIFE staff confirmed this isn't true.
The aquarium does have another penguin named Basil but she is not related to Pesto.
Pesto — who was visited by musician Katy Perry while she's in Melbourne ahead of performing at the AFL grand final — has become a true celebrity and attracted visitors from around the world, Early said.
"The reaction to Pesto has been actually unlike anything we've ever seen. We've never really experienced this kind of hype level of an animal. It was just kind of luck that he came such a sensation", Early said.
But the fame has not gone to his head, Early said.
"Honestly, he doesn't really care, he just wants to get more snacks really.
"The only time he really kind of knows what's going on is when we have people actually doing the wrong thing".
If people are banging on the barrier of the penguin enclosure it can upset the animals, she explained.
