The Rio Grande went dry in Albuquerque for first time in 40 years. A key fish habitat went with it.

• For the first time in four decades, North America's fifth-longest river went dry in Albuquerque, New Mexico, last week.
• Habitat for the endangered Rio Grande silvery minnow went with it.
• A debt owed to Texas hampers New Mexico's ability to store extra water.

ALBUQUERQUE, N.M. – For the first time in four decades, North America's fifth-longest river went dry in Albuquerque last week. Habitat for the endangered Rio Grande silvery minnow – a shimmery, pinky-sized native fish – went with it. 

Although summer storms have made the river wet again, experts warn that drying this far north is a sign of an increasingly fragile water supply and that current conservation measures may not be enough to save the minnow and still provide water to nearby farms, backyards and parks.

The minnow inhabits only about 7% of its historic range and has withstood a century of habitat loss as the nearly 1,900-mile-long river was dammed, diverted and channeled from Colorado to New Mexico, Texas and northern Mexico.

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In 1994, the U.S. government listed the minnow as endangered. Scientists, water managers and environmental groups have worked to keep the fish alive – as required by the Endangered Species Act – but the efforts haven't kept pace with demand for water and climate change.

Years of drought, scorching temperatures and an unpredictable monsoon season are zapping what's left of its habitat, leaving officials with little recourse but to hope for rain.

When parts of the river dry out, officials use hand nets and seines to pull fish from warm puddles and relocate them to still-flowing sections of the river.

The minnow's survival rate after being rescued is slim – just over 5% – due to the stress of warm, stagnant water and being forcibly relocated.

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Over the years, the government has bred and released large numbers of silvery minnows, but for the species to recover, it always comes down to habitat, officials say.

And few options remain to get significantly more water into the river.

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Debt hampers New Mexico's water supply

Historically, one way to send more water into the river has been to release it from upstream reservoirs. But this year, New Mexico has been unable to store extra water because of a downstream debt it owes Texas as part of a compact. 

Deep into the driest period the West has seen in 1,200 years, the river wasn't replenished by rainstorms that came in June.

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To keep more water in the Rio Grande, the state and irrigation districts are offering to pay farmers to leave fields unplanted, but so far, few have opted in. 

In New Mexico, small-scale farming is the norm and many farmers water their fields with centuries-old earthen canals that run through their backyards, maintaining the land for cultural reasons too.

By fallowing their fields, farmers would help save water for the minnow and alleviate the debt to Texas.