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

[2] This small fish reaches a maximum standard length of 4.2 cm (1.7 in).

[2] Later it was discovered just across the border in several wells near São Francisco do Guaporé in the Brazilian state of Rondônia.

[3] This species is threatened by environmental degradation due to pollution, water extraction for drinking and irrigation, mineral extraction, and associated erosion.

[2] It is often killed when accidentally caught from wells because of a superficial resemblance to leeches.