Diane Vick, 65, and Thomas J. Vick, 64, both were flown to a Las Vegas hospital after they tried to stop their dogs from fighting Saturday evening, Bullhead City police said.
The couple's 40-pound boxer and cocker spaniel got into a fight and the four other dogs then joined in, authorities said.
Police Lt. Nick Sessions said the boxer turned on the Vicks and began attacking them.
Thomas Vick died Sunday morning from severe bites from the boxer. He taught social studies at Mohave High School.
The cocker spaniel also died from its injuries.
Police said the five remaining dogs are being held in a 10-day quarantine by animal control and will be euthanized, according to a request by the Vick family.