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Peanut Butter and Jellyfish: Delicious Sandwich Ingredient Gets Marine Twist

Picture of a young moon jelly after being fed peanut butter
A young moon jelly on day one of the peanut butter feed experiment. Photograph courtesy P. Zelda Montoya and Barrett L. Christie.

Yes folks, it’s happened. Someone has finally combined peanut butter and jellyfish for some very interesting results.

Staff at the Children’s Aquarium at Fair Park in Dallas, Texas, wanted to see what would happen if they fed their young moon jellies a slurry of seawater and peanut butter.

“Peanuts in general have quite a bit of protein,” said Barrett Christie, aquarium supervisor. “[And] we have read quite a number of studies where peanut meal has been substituted as a marine protein in feed.”

So aquarist P. Zelda Montoya put some creamy peanut butter in a blender, along with seawater, and emulsified it like one would a salad dressing. After chilling the mix for a couple of days, Montoya then fed it to about 250 young moon jellies (Aurelia aurita) in her care.

The jellies actually seemed to do just fine.

“There’s a significant amount of protein in [peanut butter] and the jellies were able to grow at almost a normal rate,” said Christie. “Honestly, we didn’t think it would work.”

Picture of two moon jellies on day 16 of peanut butter experiment
Two moon jellies on day 16 of the peanut butter experiment. The smaller one on the left has just been fed. Photograph courtesy P. Zelda Montoya and Barrett L. Christie.

It takes about three months for young moon jellies to get about an inch (2.5 centimeters) in diameter on a normal diet of sea monkeys, the aquarium supervisor explained. (See “‘Immortal’ Jellyfish Swarm World’s Oceans.”)

They’ve kept the original group of jellies on their experimental peanut butter feed, and although their growth rates have tapered off a bit—and the normally opaque invertebrates have taken on a brownish tinge—the animals are still growing.

“We’re going to see if we can continue to raise them to complete their lifecycle and put down polyps,” Christie said. If they can get their peanut buttered jellyfish to produce the next generation, that would be a good indication that the animals are healthy, he explained.

The only downside? The tanks housing the experimental animals now smell strongly of peanut butter. Christie said that it’s hard for Montoya, who cares for the jellies, to be around peanut butter now. (See also “Creation of the world’s first Peanut Butter and Jellyfish.”)

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