There's love in the waters of lower Colorado River. After more than two decades away, the endangered razorback sucker is once again spawning in the Grand Canyon, just two years after its return.

Thought to be extirpated, or locally extinct, from the lower Colorado in Grand Canyon National Park, a single razorback sucker was spotted in 2012, motivating biologists with the U.S. Fish and Wildlife Service to release several tagged specimens back into the river. Until then, the only natural population of razorback suckers -- characterized by their bony keel-like spine -- was in Lake Mead National Recreation Area.

Now, FWS has confirmed the tagged specimens, two years after being reintroduced, are spawning -- with several larval suckers observed throughout the river. Once developed, the little fish can grow to be up to three feet in lenghth.

"This exciting news suggests that Grand Canyon is becoming a significant basin-wide haven for the endangered fishes in the Colorado River," said Lesley Fitzpatrick, a biologist with FWS.

The razorback sucker -- which, along with other natives like the humpback chub, had its habitat dramatically disrupted by the construction of the Glen Canyon Dam in the 1960s -- has been federally protected since 1991 and on Colorado's endangered species list since 1979.

Biologists believe the suckers' spawning conditions have been improved by a series of massive manmade floods instigated by the U.S. Department of the Interior in order to replenish sandbars along the banks of the sediment-starved river.