PITTSFIELD -- Give a child a piece of paper and a small box of crayons and ask for a picture of some frogs. Chances are a green crayon will color in the frogs and much of the background. Visit the Berkshire Museum Aquarium with your young artist, and afterward, the whole box of crayons will come into play.

They aquarium's newest display brings many-colored, poison dart frogs to the temperate Berkshires -- and represents only a few of the approximately 170 species found in tropical America. In the wild, these dangerous, often deadly amphibians are critically endangered because of habitat loss from logging, deforestation and farming. Overcollecting and predation also threaten their survival, but a fungal disease fatal to all amphibians has threatened them still more.

And while not all are dangerous, three or four species are very dangerous to humans, including the golden poison dart frog, which in the wild carries a poison 200 times more potent than morphine, with enough toxin in one animal to kill 10 people.

Today, nearly 100 percent of the spectacularly colored, 2 1/2-inch or smaller dart frogs seen in zoos and aquariums are born in captivity and have lost the toxicity that their bodies don't manufacture but acquire -- in the wild -- when the frogs ingest insects and spiders carrying toxins.

Dart frog keepers, like the Berkshire Museum Aquarium Manager Scott Jervas, feed their charges small insects, like harmless fruit flies, that they raise for the purpose. So the frogs on display here are as harmless as our spring peeper.

The aquarium's displays, unlike the more static displays common to many museums, change constantly, growing and evolving. This living display appears directly to the left upon entering the darkened space underground.

The 5-foot, all-glass tank, part water and part land, is equipped with an automatic mister to re-create humid rain forest conditions. Immediately, a profuse growth of authentic tropical rain forests plants from Central and South America greet the visitor, and hidden within are six species of frogs, among the smallest and most colorful in the Americas.

Casual visitors will need to be patient, as the tiny boldly colored frogs have mastered the art of hiding in plain sight, except while feeding on minute fruit flies.

If no movement shows where they are hiding, look beneath the tropical ferns, figs, orchids, begonias, spike moss and pieces of bark.

Jervas credits Fred Gagnon from Magic Wings Butterfly Conservatory in South Deerfield for his help with layout and fabrication of the enclosure. From his own collection of dart frogs and plants, Gagnon helped stock the exhibit, along with help from Black Jungle Terrarium Supply in Turners Falls.

Since opening to the public February, the smallest species, the phantasmal or tri-color dart frog, has bred. The female laid her eggs not in water but on the underside of a plant leaf.

The tadpoles hatched and wiggled onto a male's back to be taken to the water end of the display, where Jervas has netted them for relocation to an incubator tank. When large enough, they will return to the display. Jervas explains that in addition to caring for the tank, trimming the fast-growing plants -- all native to the tropics -- and the frog inhabitants, he must also raise different sizes and species of fruit flies as food for his charges, feed, prune plantings, monitor temperature, humidity and light levels, and answer a slew of visitors' questions.

He hasn't yet been asked for a box of crayons by one of his many young visitors, though.