Inshore Lizardfish, Synodus foetens

Inshore Lizardfish, Synodus foetens. Fish caught from coastal waters off Caye Ambergris, Belize, June 2013. Length: 15 cm (5.9 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Inshore Lizardfish, Synodus foetens. Fish caught off the Dunedin Causeway, Dunedin, Florida, March 2011. Length: 25 cm (9.8 inches). Catch, photograph, and identification courtesy of Ryan Crutchfield, Tampa, Florida.

Inshore Lizardfish, Synodus foetens. Fish caught from coastal waters off Ft. Lauderdale, Florida, May 2022. Length: 25 cm (9.8 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida.

Inshore Lizardfish, Synodus foetens. Fish caught from coastal waters off Key Largo, Florida, March 2012. Length: 26 cm (10 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

The Inshore Lizardfish, Synodus foetens, is a member of the Lizardfish or Synodontidae Family, that is known in Mexico as chile apestoso. Globally, there are thirty-seven species in the genus Synodus, of which eleven are found in Mexican waters, six in the Atlantic and five in the Pacific Ocean.

The Inshore Lizardfish vary in color with a light brown to olive background with a greenish cast. Their head is brownish with light mottling on the top and sides transitioning to pale yellow ventrally. They have a mid-lateral stripe that has eight obscure diamond-shaped blotches that vary from fish to fish in occurrences and intensity that fade with maturity. Ventrally they are white, silvery white or yellowish. Their adipose fin has a dark spot posteriorly, their caudal base has a dark spot on top, their caudal fin has a dark lower lobe and dark margin,  and their pectoral fins are dusky, light green or yellowish. Juveniles have dark spots on their sides.

The Inshore Lizardfish has a very elongated body, cylindrical or cigar-shaped. They vary in color with a light brown to olive background with a greenish cast. Their head is brownish with light mottling on the top and sides transitioning to pale yellow ventrally. They have a mid-lateral stripe that has eight obscure diamond-shaped blotches that vary from fish to fish in occurrences and intensity that fade with maturity. Ventrally they are white, silvery white or yellowish. Their adipose fin has a dark spot posteriorly, their caudal base has a dark spot on top, their caudal fin has a dark lower lobe and dark margin, and their pectoral fins are dusky, light green or yellowish. Juveniles have dark spots on their sides. Their head is broad and flattened and has a pointed triangular snout, mid-sized eyes, and a large mouth that extends beyond the eyes and is equipped with numerous slender teeth on both jaws and the roof of the mouth. Their adipose fin is small; their anal fin has 11 to 13 rays and has a base that is longer than the dorsal fin base; their caudal fin is forked; their single dorsal fin has 10 to 13 rays and is located mid-body half way between the center of the eye and the adipose fin; and the pelvic fins are closer to the anus than the snout tip. Their lateral line is prominent. They are covered with small scales.

The Inshore Lizardfish is a solitary demersal species that are found inshore over soft bottoms at depths up to 200 m (660 feet) within the continental shelf. The juveniles reside in estuaries and avoid predation. With maturity they will travel long distances for new habitats. They reach a maximum of 48 cm (19 inches) in length with the females being larger than the males. They reach a maximum weight of 0.9 kg (2.0 pounds). They are a partially submerged lie-in-wait ambush predators that consume primarily fish and smaller amounts of crabs, cephalopods and shrimp. Reproduction is oviparous being dioecious with separate males and females; fertilization is external. The females deposit their eggs randomly that attach to the substrate where they are left to fend for themselves with pelagic larvae. The Inshore Lizardfish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Inshore Lizardfish is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the east coast of the Yucatán Peninsula in the Caribbean.

The Inshore Lizardfish is most likely confused with the Sand Diver, Synodus intermedius (caudal fin with 3 to 5 bars across both lobes; black rectangular shoulder patch).

From a conservation perspective the Inshore Lizardfish is currently considered to be of Least Concern, with stable, widely distributed populations. They are caught very frequently by shrimp trawlers and experience a very high mortality rate. They are a common by-catch of recreational anglers and considered by most to be a nuisance fish but retained by subsistence fishermen.