THEY’RE BIG AND THEY’RE BACK
Arapaima fish that can grow to 10 feet return to zoo
They’re growing and learning their targets during daily training, and soon they will venture off to the big tank.
Only 9 inches long when they arrived two years ago at the Milwaukee County Zoo, two arapaimas have been kept in separate tanks until they grow large enough to be with the big kids.
Aquarium and Reptile Curator Shawn Miller said the giant fish will be introduced with the other inhabitants of the zoo’s 55,000gallon Amazon River Basin tank probably in May.
For zookeepers like Miller, the day the two as-yet-unnamed arapaimas finally swim into the big tank will be nerve-wracking. Sort of like parents at school bus stops anxiously waving goodbye to their kids on the first day of kindergarten.
“There’s always nerves when moving an animal into an exhibit, especially a multi-species exhibit. There’s definitely going to be stress factors — for both the fish and the keepers,” Miller said.
The zoo hasn’t had arapaimas since 2004. One of the largest freshwater fish in the world, the South American natives can top out at almost 10 feet. Torpedoshaped with dorsal fins located near its tail, arapaimas have been around since dinosaurs stomped around the planet.
“They’re very unique. When they’re on the exhibit, they’ll stand out because there’s nothing else that looks like them,” Miller said.
Their iridescent green and red scales, resembling the monster in the 1954 cult film “Creature from the Black Lagoon,” were used to adorn ladies’ dresses in the 1930s. One of the arapaimas has more of a golden hue, and their pretty pink tails are part of their natural coloration. It’s possible the fish may change their colors a bit when they move into the new tank, Miller said.
Though they have gills, arapaimas are surface breathers, occasionally poking their heads out of the water to gulp air. Miller said that’s likely because they live in stagnant, oxygen-deprived waterways in the Amazon River basin.
Their numbers plummeted due to overfishing decades ago, but now sport anglers fish for them under catch-andrelease rules. They’re also raised in fish farms and marketed as cheaper to eat than halibut or Chilean
sea bass.
In the wild they’re predatory eaters, dining on fish and small mammals that venture too close to the water’s edge. At the zoo they snack on herring, smelt, trout, anchovies and sardines plus food pellets. Their mouths make a vacuum as they suck in their dinner, creating a popping noise.
The zoo’s two arapaimas are living in separate small tanks adjacent to the large aquarium that will soon become their new home.
Milwaukee’s newest arapaimas are now 31⁄2 to 4 feet long. They have been kept separate for two years as they grew, otherwise two redtail catfish in the Amazon tank would have quickly gulped them down, Miller said.
Each day Miller and the other zookeepers train the arapaimas to hit a target with their nose, dipping a plastic purple circle and yellow triangle into the water. When the fish poke their respective targets they’re rewarded with food pellets.
Target training is done so the fish will come to a certain spot for veterinary checkups.
The zoo’s new arapaimas were farm-raised and came from a California wholesale fish distributor.
“They’re one of my favorite fish,” Miller said. “We’re one of the few zoos with such a large tank for an Amazon exhibit. Getting arapaimas back out will be a focal point of the tank.”