Umbra pygmaea (DeKay, 1842)
Eastern mudminnow
Umbra pygmaea
photo by The Native Fish Conservancy

Family:  Umbridae (Mudminnows)
Max. size:  13.7 cm TL (male/unsexed); 15 cm TL (female)
Environment:  demersal; freshwater; pH range: 6 - 6.5; dH range: 3 - 8, non-migratory
Distribution:  North America: Atlantic and Gulf slopes from southeastern New York (including Long Island) to St.Johns River drainage in Florida and west to Aucilla River drainage in Florida and Georgia, USA (Ref. 5723). Introduced (but very localized) to central and western Europe (Ref. 59043).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 14-15; Anal spines: 0-0; Anal soft rays: 8-11. Body robust, thick, little compressed; head bluntly conic; snout short, equal to diameter of eye; mouth moderate, jaws short, mandible protrudes slightly beyond tip of upper jaw, premaxillaries not protractile. Gill rakers short and numerous. Dorsal inserted near pectoral than caudal base; pelvic inserted just before origin of dorsal , rays of depressed fin reaching to about 3rd anal ray. Caudal fin rounded, with 18-20 rays (Ref. 2196). Pigmentation: yellowish green with 10-12 narrow lateral dark stripes; a dark stripe through eye; a black basicaudal bar; lower jaw pale; fins plain. Also Ref. 40476.
Biology:  Inhabits quiet streams, sloughs, swamps and other wetlands over sand, mud and debris, often among dense vegetation. Juveniles also found among aquatic vegetation, often forming schools of 10-12 individuals (Ref. 39069). An introduced species in Europe which usually occurs in small isolated ponds and peat bogs (Ref. 59043). Oviparous, larvae remain in algal nest for about 6 days (Ref. 39067). Spawning takes place in April and May (Ref. 30578). Feeds on insect larvae, worms, mollusks, crustaceans alevins. Experimental studies show that this species can tolerate acidic environment, particularly, at ph values ranging from 4.0 to 7.0 where no mortality or significant changes in blood plasma osmolarity and haematocrit was observed (Ref. 59260).
IUCN Red List Status: Least Concern (LC); Date assessed: 01 March 2012 Ref. (130435)
Threat to humans:  harmless


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