Species: Fundulus xenicus, Diamond Killifish

Fundulus xenicus (Jordan & Gilbert, 1882)

Diamond Killifish

Body short, compressed, diamond shaped in adult, moderately deep (1/3-1/2 SL); head flattened above, with concave upper profile; eye large, about 2X length of lower jaw; front nostril not tubular; cover of eye not continuous with head skin; mouth small, at front, oblique, protrusible, lower jaw projecting, robust, expanded in center, without pores; jaws with an outer row of slightly compressed dagger-like teeth and an inner band of simple conical teeth; gill rakers poorly developed, 14-15; no spines in fins; dorsal fin short based, at about midbody, over anal fin, 7-16 rays; anal fin with 3rd fin ray branched; male with larger anal fin; tail fin rounded; pectoral with narrow base, rounded, inserted low on side; pelvics inserted behind pectoral base; large smooth scales, 24-26 along mid-side; 9 or more scale rows between dorsal and anal fins; body without lateral line.

Male dark grey-green, with 15-20 narrow whitish bars on flank; dorsal and anal fins grey green, with whitish spots; tail fin with whitish and dark grey spots. Female greenish, with fewer and broader bars on body; dorsal anal and tail fins unspotted.

Reaches 6 cm.

Lives in freshwater to hypersaline lagoons, estuaries and mangroves.

Depth range: 0-1 m.

The N Gulf of Mexico.