So hippo to see you!

An adorable baby hippopotamus met his older sister for the first time while frolicking underwater in an enclosure at the Cincinnati Zoo.

A video clip posted online by the zoo shows 3-week-old Fritz eagerly waddling into Hippo Cove ahead of lumbering mom Bibi on Wednesday.

Older sister Fiona, 5, appeared curious when Fritz approached but followed cues from their mother and backed away before the Nile hippo calf was able to bump noses with her, the zoo said.

“This first intro went very well,” said Christina Gorsuch, the zoo’s director of animal care.

“Bibi was appropriately protective of Fritz but was not aggressive toward Fiona. The exposure was brief but a great first step.”

Fritz was born Aug. 3 following what the zoo said in April was an unexpected pregnancy while Bibi was on birth control medication.

“We weren’t planning to welcome a baby this soon, but nature found a way and ignored our calendar,” Gorsuch said at the time.

Fritz’s dad, Tucker, was acquired from the San Francisco Zoo in September.

Zookeepers want to make sure that Fiona, Fritz and Bibi are comfortable together before allowing Tucker to join the hippo clan, known as a “bloat.”

It’s unclear when that will happen and Hippo Cove will be closed to the public — with its live cams turned off — to give the creatures privacy during future introductions, the zoo said.

Hippos, which weigh up to 8,000 pounds each, are the world’s heaviest land animals other than elephants.

In the wild, they live in and around the lakes and rivers of sub-Saharan Africa, with an estimated population of no more than 130,000, according to the World Wildlife Fund.

The species is listed as vulnerable to extinction by the Switzerland-based International Union for Conservation of Nature, which says the animals’ primary threats to survival are loss of habitat to real estate development and poachers who kill them for meat and ivory.