Loach Minnow

DESCRIPTION:
Loach minnow are small elongated fish that are slightly compressed from side to side, sometimes humped behind the nape, and flattened ventrally. The mouth is small, terminal, and oblique with no barbels. The upper lip and snout are connected by a broad frenum, the gill openings are restricted, and the air bladder is reduced. Scales are absent or deeply embedded on the breast, belly, and the anterior and midline of back. They are olivaceous in color, blotched and speckled with dark brown or black. The belly is immaculate cream color to white. Dirty white to cream colored blotches are present before and behind the dorsal base and on the upper and lower edges of the caudal peduncle, the latter extending onto the proximal caudal fin. Loach minnow also have distinctive whitish spots near the base of the dorsal and caudal fins.

DISTRIBUTION & STATUS:
Endemic to Gila River basin in Arizona, New Mexico, and Sonora. Increasingly rare, Loach Minnow has been recorded from the headwaters of Rio San Pedro in Sonora in 1951, but has since not been recorded from the upper parts of that basin in either Arizona or Sonora. Federally listed as threatened, critical habitat for Loach Minnow is nearly identical to that for Spikedace. Threats to this species include but are not limited to, livestock grazing, dams, mining, logging, groundwater pumping, water diversion, and the introduction of non-native species.

HABITAT:
Loach Minnow are specialized fish found in sand to gravel runs and riffles. Adults are often associated with beds of coarse filamentous algae in shallow, swift, and turbulent reaches. They occur in elevations between 330 -2200 m, almost exclusively in streams with clean, loose, gravel bottoms.

FOOD HABITS:
Opportunistic, bottom-feeding insectivores. They actively seek their food among bottom substrates rather than pursuing items in the current.

REPRODUCTION:
Breeding males develop vivid red to red-orange on the fin bases and adjacent body surfaces; on the mouth and lower head, including the branchiostegal rays; often over the abdomen; and on the ventral caudal peduncle. Tuberculation, the development of hard bumps on fins and scales during breeding season, is restricted mostly to males. Reproductive females have a yellow to pale orange pigmentation on the lower body and fins and sometimes a few diminutive tubercles develop on the pectoral rays.