Phreatobius sanguijuela Fernández, Saucedo, Carvajal-Vallejos & Schaefer 2007

Distinguished from other siluriform genera by having the following combination of characters: dorsal and ventral procurrent caudal-fin rays extended rostrally, dorsally reaching a vertical position on dorsal-fin base posterior to dorsal-fin insertion, ventrally continuous with anal fin; caudal fin round; all anal-fin rays unbranched; mouth prognathous, with jaws displaced dorsally on head; adductor mandibulae muscle hypertrophied, covering most of skull and inserting posteriorly onto first neural spine; first pectoral-fin ray soft, not spinous; bright red in life. Differs uniquely from its congeners by the absence of eyes, presence of 25-34 dorsal procurrent caudal fin rays; 14-16 ventral procurrent caudal fin rays; 45-46 vertebrae (Ref. 59347).

Dorsal spines (total): 0; Dorsal soft rays (total): 7; Analsoft rays: 19 - 20; Vertebrae: 45 - 46

Occurs in artificial wells with transparent water, depth range 6 to 12 m and diameter of approximately 1 m (Ref. 59347). The water in the wells is used locally for human consumption. This fish is often mistaken for parasitic leeches " sanguijuelas" due to its bright, blood-red color and vermiform shape. For this reason, this is killed upon incidental capture when extracting drinking water from wells.

Phreatobius sanguijuela is a South American species of heptapterid catfish that lives in underground waters.

This species was first discovered in a hand-dug well located within the Paragúa River drainage, a tributary of the Guaporé (Iténez) River in Bolivia. Later it was discovered just across the border in several wells near São Francisco do Guaporé in the Brazilian state of Rondônia. This species is threatened by environmental degradation due to pollution, water extraction for drinking and irrigation, mineral extraction, and associated erosion. It is often killed when accidentally caught from wells because of a superficial resemblance to leeches.

This small fish reaches a maximum standard length of 4.2 cm (1.7 in). P. sanguijuela differs from P. cisternarum in a number of ways, but the main differences are the absence of eyes (which are present in P. cisternarum).