October 4, 1993 – The Center filed a lawsuit against the U.S. Fish and Wildlife Service for failing to designate critical habitat for the loach minnow and spikedace.
March 8, 1994 – The lawsuit resulted in the designation of 200 river miles of critical habitat.
October 13, 1994 –The U.S. Fish and Wildlife Service suspended its designation of critical habitat on a legal technicality.
1996 – The Center filed suit against the Bureau of Land Management, which resulted in a determination that 19 grazing allotments along the Gila River adversely affected endangered species, including the loach minnow and spikedace.
1997 – The Center filed another lawsuit against the Fish and Wildlife Service for failing to designate critical habitat.
1998 – The Center settled a lawsuit with the U.S. Forest Service that banned cattle from streamside habitats on 57 grazing allotments.
1999 – The Center participated in a negotiation with Arizona Public Service, which resulted in the decommissioning of both hydro-power plants on central Arizona's Fossil Creek and the return of full water flows to the river.
April 25, 2000 – The Fish and Wildlife Service designated 900 river miles as critical habitat for the loach minnow and 800 miles for the spikedace.
October 2000 – The Center filed suit challenging 89 livestock grazing allotments on five national forests in the Gila River basin.
2001 – In response to a notice of intent to sue filed by the Center, the Bureau agreed to review the impacts of livestock grazing on 341,000 acres of public land in Arizona.
2006 – The Center launched a long-term campaign to protect the Verde River from water diversions and groundwater pumping.
March 2007 – Following a lawsuit by the Coalition of Arizona/New Mexico Counties for Stable Economic Growth and the New Mexico Cattle Growers' Association, the Fish and Wildlife Service withdrew its previous critical habitat designation. Former Deputy Assistant Secretary for Fish and Wildlife and Parks Julie MacDonald made a policy decision to define occupied habitat as occupied within the previous 10 years, which effectively reduced the area to be considered for critical habitat. After soliciting a new round of public comments, the Service designated 522.2 river miles as critical habitat for the fishes.
November 2007 – Pressure from the Center led to reintroduction of loach minnows and spikedace into Fossil Creek. In the same month, the Center filed suit against the Service for slashing critical habitat for the spikedace and loach minnow.
May 22, 2008 – The Center filed a notice of intent to sue the U.S. Forest Service for failing to consult with the Fish and Wildlife Service while management of Fossil Creek continued to adversely affect the loach minnow and spikedace, along with other imperiled native fish and their habitat.
May 5, 2009 – A judge ruled for the fish in the critical habitat lawsuit brought by Arizona and New Mexico counties and the New Mexico Cattle Growers' Association, concluding that it was more likely that the species' protected habitat was not expansive enough than that it was overinclusive, as the plaintiffs had asserted. The Fish and Wildlife Service agreed to consider designating additional critical habitat for the fishes.
July 20, 2010 – The Center sued the U.S. Forest Service for failing to monitor and protect habitat and endangered species in Arizona and New Mexico national forests — including the southwestern willow flycatcher, New Mexico ridge-nosed rattlesnake, Chiricahua leopard frog, Apache trout, loach minnow, Mexican spotted owl and spikedace.
October 27, 2010 – The Fish and Wildlife Service proposed to protect nearly 900 river miles for the spikedace and loach minnow, as well as to upgrade both fishes' status from threatened to endangered.
February 2014 – The Center filed a cease-and-desist notice with the Federal Aviation Administration and Arizona's Department of Transportation to stop spending money for the construction of a new taxiway at the Sierra Vista Muni-Libby Airport. Initial work to support the taxiqway had already begun without an analysis of environmental harm, such as to the San Pedro River and its wildlife, including the loach minnow.