- Although the flesh of the almaco jack is considered quality table fare, the species has been associated with ciguatera poisoning, a seldom fatal stomach irritation.
- The almaco jack is susceptible to tapeworm parasites in the caudal peduncle area, but the meat can be eaten safely if affected portions are cut away.
Lookdown are members of the jack family and are often confused with moonfish, but the head of the lookdown is smaller and the fins are longer. Their name comes in part from their habit of hanging just above the sea floor in a tilted manner that makes it appear that they are looking downward. Coloration is metallic silver with highlights of gold, green, blue or purple. The primary silver color is so reflective in nature that photographers have difficulty taking pictures of lookdown with artificial light.
Their bodies are very flat, so much so that they can actually be difficult to see when looking directly at them from the front. The head has a steep forehead that nearly makes it appear that they have no definable head. The eyes are located high on the head. The combination of eye placement and head angle contributes to the image of the fish always looking down.
A distinctively long filament extends from the dorsal fin, which begins with 9 spines and tapers down to 23 short, connected rays. The nearly identical anal fins have 3 spines and 18 soft rays, as well as the long filament. The pelvic fin is relatively small. The pectoral fin has 20 soft rays.
Lookdown favor small fish and invertebrates. Preferred foods include small fishes such as mollies, anchovies, minnows and silversides. They also consume small crabs, shrimp and worms. Talented hunters, they can swim with short bursts of speed to attack aggressively.
Lookdown are found in the western Atlantic Ocean from Maine in the United States to Uruguay in South America. They are most common around Florida, Bermuda, the Bahamas and along the Central and South American coasts. They are found in smaller numbers around the Caribbean Sea and Gulf of Mexico.
Lookdown populate mid-depth water in the shallow inshore waters of the continental shelf and the surf areas just off beaches; occasionally they inhabit brackish water. They prefer sea bottoms of sand, silt and mud. Young lookdown can occasionally be found in river estuaries. Adults congregate around structures such as bridge and dock foundations, jetties, piers and buoys. They can be found in water as deep as 175 feet, but usually are found in water between 5 and 30 feet deep. They will create small schools, but mostly they travel in pairs or small groups.
- The largest known lookdown weighed 4 pounds, 10 ounces and was landed off the coast of Brazil.