Vex Experts’ Mysterious Breeding Habits of Aquarium Fish

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PENYABANGAN, Indonesia — It took a broken air conditioner for Tom Bowling to figure out — after nearly eight months of failure — how to farm the coveted pink-yellow tropical fish known as spotted anthias.

Bowling, an ornamental fish breeder based in Palau, had kept the fish in cool water, trying to replicate the temperatures that deep-sea creatures are usually found in. But when the air conditioner broke, the water temperature rose a few degrees overnight — with surprising results. “They started spawning – they went crazy, laying eggs all over the place,” Bowling said.

Experts around the world are tinkering with water temperature, lighting up with lights, and trying out various mixtures of microscopic food particles in hopes of ending up in the particular, particular set of conditions that will entice fish to dive. ornament to reproduce. Experts hope to divert the aquarium fish trade away from wild fish, which are often taken with poisons that can harm coral ecosystems.

Most of the millions of glittering fish that roam around saltwater aquariums in the United States, Europe, China, and elsewhere come from coral reefs in the Philippines, Indonesia, and other tropical countries.

Trappers often knock them out with chemicals like cyanide. They are then transferred to middlemen and then flown around the world, ending up in aquariums in homes, shopping malls, restaurants and doctor’s offices. Expert estimate “large percentages” die along the way.

Part of the problem: Only about 4% of saltwater aquarium fish can be bred in captivity, largely because many have elaborate reproductive cycles and delicate early stages that require sometimes mysterious conditions that scientists and breeders find it difficult to reproduce.

For decades, experts have been working to unlock the secrets of marine fish farming. Breakthroughs don’t come quickly, said Paul Andersen, campaign manager for Coral Reef Aquarium Fisheries, which works to support sustainable fishing in coral reef aquariums.

“It takes years of investment, research and development, often to achieve incremental milestones,” he said. And then even longer, he said, to bring newly captive-bred species to market.

The Moorish Idol, a black and yellow striped fish with a mane-like backbone, requires a lot of space. Green squiggle-striped mandarins prefer to spawn just before sunset, requiring very particular light cycles to breed in captivity. As Bowling discovered in Palau, spotted anthias require very specific temperatures.

“You have to pay attention to all the parameters that will make a fish happy,” Andersen said. “Some species are really gentle and delicate and sensitive to this stuff.”

After the fish spawn, farmers often find themselves faced with the most difficult part of the process: the larval period, which is the period just after the fish hatches, before it turns into a juvenile. The water flow must be just right, but they are so fragile that they must be protected from filters and even the walls of the tank.

First feeding is also crucial, said Andrew Rhyne, professor of marine biology at Roger Williams University in Rhode Island. For the first few days, many fish larvae have no eyes or mouths, living instead on their yolk.

“When they finally form eyes or mouths, it’s so important to have created an environment that allows them to get a first bite of zooplankton so they can get a little stronger and keep growing,” said Rhyne. “That’s kind of the magic of it all.”

Often that first bite is an essential part of the ocean food system that holds its own mysteries: Called copepods, they are microscopic crustaceans that provide vital nutrients to larval fish and are essential for farmers around the world.

At the University of Florida’s Tropical Aquaculture Laboratory at Ruskin – where the “Dory” bluefish popularized by the movie Finding Nemo was first successfully bred – Associate Professor Matt DiMaggio and his students worked on the production of copepods. But even copepods have proven difficult to breed.

Dead more than 10,000 miles from the Florida lab on the tropical north coast of Bali, Indonesia, famed fish breeder Wen-Ping Su wanders between large cement aquariums, his own recipe for zooplankton spinning in a tank circular nearby.

Su said he has 10 different keys to success that he has been developing for nearly two decades. These keys have allowed him to breed fish that no one else has, including striped king angelfish and black-bodied, orange-rimmed pinnatus bats.

But when asking Wen-Ping Su if he wants to share any details, his answer comes quickly, his hands crossing to form an X in front of his big smile: “No”.

It’s the same sentiment shared by Bowling, which stops when asked to share the secrets of its most high-profile successes. “That’s the part I really don’t want to tell you,” he laughs.

These secrets are their livelihood. Blotched Bowling anthias high after broken air conditioner are listed for $700 on his company’s website. Su’s bred fish also sell for hundreds of dollars online.

But over the past five years, some organizations — such as Rising Tide Conservation, a nongovernmental organization dedicated to developing and promoting aquaculture — have worked to promote information sharing, DiMaggio said.

“It helped accelerate the number of species we were able to breed during this time and the variety of species as well,” he said, highlighting species such as wrasses, butterflyfish and thongs.

Rhyne’s research lab – which includes the breeding of toothy triggerfish and red-striped yasha gobies – also strives to share its research with breeders.

But Rhyne and other breeders admit that it’s unlikely that all aquarium fish will be bred in captivity because some are just too picky, while others are so abundant in the wild.

And raising a fish doesn’t guarantee it will achieve or do well in the marketplace, Rhyne said. Captive-bred fish cost more and fish industry experts acknowledge that it will take time to convince consumers to pay more.

“How do we market aquaculture fish the same way we market organic food, you know, and demand that premium price?” said Andersen, of the Coral Reef Aquarium Fisheries campaign. “Marketing is really important.”

Associated Press video reporter Marshall Ritzel reported from Florida. Kathy Young contributed to this report from New York. Andi Jatmiko, Edna Tarigan and Tatan Syuflana contributed from Indonesia.

Follow Victoria Milko on Twitter: @thevmilko

The Associated Press Health and Science Department is supported by the Howard Hughes Medical Institute Department of Science Education. The AP is solely responsible for all content.

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