James Cooper is quite used to being bitten, nibbled and even sucked on by his charges.

It's all part of a day's working caring for the several hundred sometimes friendly, sometimes rambunctious and very often shy native fish in his care at the Genesis Energy Freshwater Aquarium at the Tongariro National Trout Centre near Tūrangi.

"I love it," he says of his job. "It's great fun."

Before James' arrival in April, the aquarium had been run by a mix of volunteers and Department of Conservation rangers but it was felt that the aquarium, opened in 2010 as a place to showcase New Zealand freshwater fish and freshwater ecosystems wasn't living up to its promise so James, who had just finished his Masters degree in freshwater ecology, was brought in as its full-time manager.


The aquarium is part of the trout centre's River Walk visitor centre and James spends a lot of his time talking to the public about fish and the species on display.

He says because New Zealand's native fish aren't showy creatures, many people have never seen them so the aquarium provides a place where they can be viewed up close. The aquarium holds specimens of virtually the full range of native fish found in the North Island.

"The original concept was to go from the mountains to the lake sort of look, but the fish had other ideas so we have redesigned it so it's more fish-friendly and shows them off better."

James says while managing an aquarium provides plenty of variety, his daily routine generally includes checking all the tanks, doing a bit of cleaning, and spending time with customers or school groups visiting the aquarium.

"A lot of people have never seen [native fish] before or they know about whitebait but don't know that they are five different species or that they grow into large fish such as the giant kokopu which can grow up to 2.5kg.

"Kids love the [long-fin] eels. A lot of people coming in are really fascinated by them especially when they find out about their life cycles. A lot of them say they think they are gross but find out they're actually quite cute.

"These guys [the eels] are pretty cool. The coolest thing is that sometimes they'll sleep upside down and people think they're dead."

James has been bitten by the eels a few times while feeding them or cleaning their tank and says the secret is not to pull away.

"You have to push into them because their teeth slope backwards and generally [they'll release].

"They generally won't bite unless you're doing something silly like pulling them out of the water. I've been wading in rivers where there's literally thousands around me and never been bitten."

The naughtiest are the mudfish, which never pass up an opportunity to bite James if they can, although happily (for him), they don't pack much of a punch.

"Every time I clean it [the mudfish tank], he comes up and he's sucking on my fingers."

James also likes the common bullies which are brought in at a young age and quickly get used to having people around.

"They're so friendly and they're always out looking at what's going on around them. They're really inquisitive."

He says his favourite fish would have to be a toss up between the red-fin bully and the koaro.

"Red-fins are just beautiful, and koaro because of where they live, what they look like, they're amazing fish. They live in fast-flowing streams and can climb up waterfalls, they stick to the bottom with their big wings and just glide in the water - but I do kind of like them all."

His most disliked fish is the pest fish gambusia, also known as the mosquito fish.

"They're from America and they were introduced all around the world in the idea that they would control mosquito larvae, but the mosquitoes breed in areas that the fish can't get to so they don't do their job, they eat all the food for the other fish, they breed like wildfire and are almost impossible to eradicate and they gang up on other fish."

One of James' upcoming priorities is to increase the aquarium's stock of fish.

Banded kokopu at the Genesis Energy Fresh Water Aquarium at the Tongariro National Trout Centre.
Banded kokopu at the Genesis Energy Fresh Water Aquarium at the Tongariro National Trout Centre.

He says while most of the tanks are near capacity, the open river tank display in the centre particularly needs more fish - another 60 or so should do it. He's hoping to get out soon to catch some more koaro, torrentfish and bluegill bullies, which all live in faster-flowing water, and because most native fish are nocturnal, that means getting out at night.

Tongariro National Trout Centre manager Bevin Severinsen says the freshwater aquarium is important because native fish are so hard to see in the wild thanks to their ability to blend in.

"The challenge is keeping them alive which is where we needed someone of James' expertise. You've got to know what you're doing to be able to keep them in captivity like this and to keep the aquarium looking its best it needs somebody with James' skills."

The Tongariro National Trout Centre is open daily from 10am to 3pm until November 30, and then 10am-4pm until May 1.