Mysterious breeding habits of aquarium fish experts

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PENYABANGAN, Indonesia – After nearly eight months of failure, Tom Bowling needed a broken air conditioner to figure out how to raise the pinkish-yellow tropical fish known as spotted anthias.

Bowling, an ornamental fish breeder based in Palau, kept the fish in cool water, trying to replicate the temperatures that deep-water creatures normally find. with surprising results. “They started spawning — going crazy, laying eggs everywhere,” Bowling said.

Experts from all over the world are fiddling with water temperatures, futzing with lights, and testing different mixtures of microscopic food particles in the hope that a specific and unique set of conditions will occur that will inspire ornamental fish to reproduce. Experts hope to shift the aquarium fish trade away from wild fish, which are often caught with toxins that can harm coral ecosystems.

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

Catchers often use chemicals like cyanide to disorient them. They are then passed on to middlemen and then fly around the world, ending up in homes, shopping malls, restaurants and aquariums in medical facilities. Experts estimate that “large percentages” die on the road.

Part of the problem: only about 4% of saltwater aquarium fish can be bred in captivity because many have very advanced reproductive cycles and sensitive early life stages that sometimes require mysterious conditions that scientists and breeders struggle to reproduce.

For decades, experts have been working to unlock the secrets of marine fish breeding. Progress does not come quickly, says Paul Andersen, head of the Coral Reef Aquarium Fisheries Campaign, which supports sustainable coral reef aquarium fisheries.

“It takes years of investment, research and development, often in incremental steps,” he said. And then, he said, the new captive-bred species are being marketed.

The Moorish idol, a black-and-yellow striped fish with a mane-like dorsal fin spine, requires a lot of space. Squiggle-striped green mandarins prefer to spawn before sunset, which requires very specific light cycles to reproduce in captivity. As Bowling discovered in Palau, spotted anties require very specific temperatures.

“You have to focus on all the parameters that will make the fish happy,” Andersen said. “Some species are really soft and delicate and sensitive to this sort of thing.”

After the fish spawn, breeders often face the most difficult part of the process: the larval period, which is the period immediately after the fish hatches, when it reaches adulthood. The flow of water should be correct, but they are so fragile that they need to be protected from filters and even tank walls.

Andrew Rhyne, a professor of marine biology at Roger Williams University in Rhode Island, said the first feeding is also very important. In the early days, many larval fish lack eyes and mouths, instead living on their yolk.

“When they finally develop eyes or mouths, it’s very important to create an environment that allows them to get that first bite of zooplankton so they can get a little stronger and continue to grow,” Raine said. “That was the magic of it all.”

Often the first bite is an essential part of an ocean food system that holds its own secrets: copepods, microscopic crustaceans that provide vital nutrients to larval fish and are a staple for breeders worldwide.

At the University of Florida’s Tropical Aquaculture Laboratory in Ruskin — where Dory, the blue fish made famous by the movie “Fining Nemon” — was first successfully bred, assistant professor Matt DiMaggio and his students are working on producing copepods. But even copepods have proven difficult to breed.

10,000 miles from his Florida lab, on the tropical north coast of Bali, Indonesia, renowned fish breeder Wen-Ping Su walks among large cement fish tanks, his zooplankton recipe playing in a nearby circular tank.

Su said there are 10 different keys to success that he has developed over nearly two decades. These switches have allowed him to breed fish like no other, including the striped king angelfish and the curly black-bodied, orange-bordered pinnatus batfish.

But when Wen-Ping Su asks if he’ll share the details, his answer comes quickly, his hands forming an X in front of his big smile: “No.”

It’s the same sentiment echoed by Bowling, who paused when asked to share the secrets of his top-level success. “That’s the part I really don’t want to tell you,” he laughs.

These secrets are their livelihood. Spotted anthias, grown after a broken air conditioner, Bowling sells for $700 on his company’s website. Aquatic fish are also sold online for hundreds of dollars.

But in the past five years, some organizations — such as Rising Tide Conservation, a nongovernmental organization dedicated to aquaculture development and promotion — have worked to encourage information sharing, DiMaggio said.

“It helped speed up the number of species we were able to grow at that time and also the diversity of species,” he said, highlighting species such as beetles, butterflyfish and tangs.

Ray’s research lab — which involves breeding toothy queen triggerfish and red-striped juvenile gobies — is working to share his research with breeders.

But Rhyne and other breeders admit that it is unlikely that all aquarium fish will be bred in captivity, because some are very difficult and others are very abundant in nature.

Raising fish doesn’t guarantee it will make it to market or perform well, Raine said. Captive-raised fish cost more, and experts in the fish industry understand that it will take time to convince consumers to pay more for them.

“How do we sell aquaculture fish the way we sell organic food and charge that premium price point?” said Andersen of the Coral Reef Aquarium Fisheries Campaign. “Marketing is really important.”

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

Follow Victoria Milko on Twitter: @thevmilko

The Associated Press Department of Health and Science receives support from the Department of Science Education at the Howard Hughes Medical Institute. AP is responsible for all content.

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