One of the smallest seahorses, about the size of a fingernail, living in seagrass in very shallow water in Florida and the Gulf.
To about 5 cm, which makes it one of the smallest seahorses in the world. It matures at about 2 cm. The snout is short, the body often carries filaments and algal growth, and the colour is highly variable — beige, yellow, green, black or mottled. It is usually found clinging to a blade of seagrass.
Young lined and longsnout seahorses are the confusion. An adult of this species is under about 3 cm with a stubby snout; the juveniles of the other two have proportionally longer snouts and go on growing well past 5 cm.
It lives on shallow seagrass flats between the surface and about 10 m, strongly tied to eelgrass and other seagrasses, and also to floating weed. It is monogamous and the male carries the eggs.
It is listed on Appendix II of CITES, like every seahorse. It is not on the US endangered species list: it was petitioned, and in July 2020 the finding was that listing was not warranted. Many popular sources say otherwise.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.