"It's crazy how big it is inside," says Josh Marsters of Middleton. "You can't tell from the outside."

Marsters, 31, and his wife, Nicole, 28, are spending a Friday afternoon wandering through the blue maze of exotic fish, eels and tree frogs.

"She loves it," Nicole says, nodding toward their 4-year-old daughter, who is dipping her fingers into a tank while a flounder hides beneath the sand. "This is the first time we've been here. We'd definitely come back."

After several years spent searching for funding and a location, the 10,000-square-foot aquarium opened two months ago next to entertainment center Monkey Bizness in a plaza at Franklin and Cole roads.

It's a work in progress. Bustling volunteers and conspicuously placed cash donation jugs are proof of that -- not to mention the sound of a power tool in the back.t

But even if it's somewhere between guppy and great white right now, there's one undeniable fact about the Idaho Aquarium: It makes a cannonball-sized splash with kids.

"It's super fun!" says Boise 11-year-old Hannah Wallstrom, who has logged half a dozen visits. "You get to touch all these fish -- and all these manta rays and sharks."

Several kid-friendly showcases -- called "touch tanks" -- are an important selling point for a modest facility that currently features a giant Pacific octopus as its most valuable inhabitant. (Sorry, she stays behind glass, kids.) Big-time exhibits will have to wait until the aquarium has become more established.

"We just started (constructing) our big seal tank," says Idaho Aquarium director Ammon Covino. "We're just short about 15 grand."

Not that excited kids are clamoring for anything more.

They bounce between tanks, giggling and pointing as they line up to feed strips of seaweed to nibbling fish. Gasping, they reach out to timidly graze the dorsal fin of a small, year-old hammerhead shark streaming past.

The aquarium is packed with school trips almost daily, Covino says. It also can be rented for sleepover events and birthday parties.

It may seem like a stroke ofgenius, but the aquarium's touch-friendly style came partly out of necessity. It's cheaper to build shorter tanks.

"We just didn't have the money to build nice, big, tall tanks," Covino says, before joking: "I guess it's a good thing we didn't get any foundations to give money."