The Aquarium Hobby's Most Common Seahorses:

A Quick Identification Guide

By Will Wooten

Although most marketers of captive-bred seahorses are fully aware of the correct scientific identification of their seahorses, many commercial and private vendors of both wild-caught and captive-bred seahorses can easily mistake one seahorse species for another. The following guide is just what it claims: a quick and easy-to-use guide to identifying the aquarium hobby's most commonly available seahorse species.

Name	Photo (click to enlarge)	Identifying Traits	May Be Confused With:

Hippocampus abdominalis Pot Bellied Seahorse max size: 32cm/13in		Largest known seahorse species, easily identified by its protruding abdomen. (hence its scientific name). Generally specimens are light in color with black or brown splotchy pattern. Very blunt spines. 25-31 dorsal rays and 12-13 body rings. NOTE: temperate species	Hippocampus ingens, which is similar in size and comes from similar temperature ranges, but whose patterning is quite different.

Hippocampus barbouri Barbour's Seahorse max size: 15cm/6in		Medium-sized seahorse. Barbour's Seahorse is most easily identified by its snout pattern; the snout usually has a ringed stripe pattern. Specimens are generally light yellow to brownish in color with white patterns and dark pinpoint spots on their sides. Sharp spines and sometimes elaborate cirri. 16-22 dorsal rays and 11 body rings.	Hippocampus histrix, which has sharp spines but lacks elaborate patterning. Hippocampus spinosissimus, which also has sharp spines but lacks elaborate patterning.

Hippocampus bargibanti Pygmy Seahorse max size: 2cm/0.75in		Tiny, very easily-distinguished seahorse that sometimes makes its way into the aquarium hobby via its host gorgonians, Muricella plectana and Muricella paraplectana. This diminutive species is usually brightly colored with contrasting tubercles to match its host gorgonian. 13-15 dorsal rays and 1 distinguishable body ring.	Hippocampus zostrae due to confusion over their common names.

Hippocampus capensis Knysna Seahorse max size: 11cm/5in		Smaller seahorse characterized by smooth body with no spines or coronet. Hippocampus capensis also has a rather short snout. Colors range from yellow to green to brownish, usually with a mottled spot pattern. Can have dark spots. 16-18 dorsal rays and 11 body rings. NOTE: subtropical species	Hippocampus kuda, which is generally larger and has more-developed spines

Hippocampus comes Tiger Tail Seahorse max size: 15cm/6in		Unique species that lives up to its name. The Tiger Tail seahorse is characterized by yellow and black splotchy patterning and a striped tiger-like tail. Well-developed, sharp spines on many specimens. Five-pointed coronet. 17-18 dorsal rays and 11 body rings.	Hippocampus erectus, whose characteristic lined pattern is one of few differences. Hippocampus kuda, which shares body shape but has a less-developed coronet and less bold body patterning.

Hippocampus erectus Lined Seahorse max size: 20cm/8in		One of the hobby's most common seahorses, currently being captive-bred by most seahorse farms across the world. Telltale characteristic is the close, mazelike striping pattern on the sides of all specimens of this species. Crown-like coronet; undeveloped body spines. Colors range from brown to bright orange and yellow with most specimens exhibiting some degree of white mottle patterning. 18-19 dorsal rays and 11 body rings.	Hippocampus ingens, whose coloring and body shape are similar, but lacks lined patterning. Hippocampus kuda, which shares body shape but has a less-developed coronet and lacks unique body patterning. Hippocampus reidi, whose coloring and body shape are similar, but lacks lined patterning.

Hippocampus histrix Thorny Seahorse max size: 17cm/7in		Large but delicate species with long, sharp, highly developed spines. Distinctive characteristics include a longer-than-normal snout and a single prominent spine directly in front of the coronet. Color is variable, ranging from light, almost pastel pink to brown. Pale splotches along the body are common, as are small dark spots. 15-18 dorsal rays and 11 body rings.	Hippocampus barbouri, which also has sharp spines but is a smaller species. Hippocampus spinosissimus, whose color is similar but whose spines are less developed.

Hippocampus ingens Pacific Seahorse max size: 30cm/12in		One of the largest and most variable seahorse species, it is often a challenge to identify. Perhaps the easiest way to identify is by process of elimination. Unique traits include high coronet with five well-defined points and a prominent eye spine. Color may range from yellow to brown to warm red, and some degree of white patterning usually is present. 18-21 dorsal rays and 11 body rings. NOTE: subtropical species	Has similarities to most all other seahorse species, although few others reach its size. None have completely identical characteristics.

Hippocampus kuda Spotted Seahorse max size: 30cm/12in		A very "common" seahorse in the trade, most truly unidentified specimens are mistakenly labeled as H. kuda. True specimens are somewhat difficult to find, though they are being captive bred. Low, rounded coronet is a telltale sign. Solid, bold colors ranging from black to pale yellow. 17-18 dorsal rays and 11 body rings.	Hippocampus erectus, whose coloring and body shape are similar, but kuda lacks lined patterning. Hippocampus ingens, whose coloring and body shape are similar, but most kuda lack white patterning and have less-developed coronets. Hippocampus reidi, whose coloring and body shape are similar, but lacks similar patterning

Hippocampus reidi Brazillian Seahorse max size: 15cm/6in		One of the most desired species in the aquarium trade, it is imported quite often. Long, thick snout, narrow body, and no spines or cirri. Can be found in a range of bold, bright colors and usually is covered with tiny black or white spots. May also have pale splotches on lateral surfaces. 16-19 dorsal rays and 11 body rings.	Hippocampus erectus, whose coloring and body shape are similar, but reidi lacks lined patterning. Hippocampus ingens, whose coloring and body shape are similar, but has more-developed spines and coronet. Hippocampus kuda, which shares body shape but has a less-developed coronet and lacks tiny spotted pattern.

Hippocampus spinosissimus Hedgehog Seahorse max size: 16cm/6in		One of several regularly-kept wild-caught seahorses in the aquarium hobby. Medium coronet and sharp, well-developed spines that may have blunt tips depending on the specimen. Variable but usually lightly colored, ranging from pale brown to greenish. Dark splotches may be present as well as dark crosshatching on tail. 17-18 dorsal rays and 11 body rings.	Hippocampus barbouri, which also has sharp spines but is a smaller species. Hippocampus histrix, which has sharp spines but is more delicate and much more narrow.

Hippocampus subelongatus West Australian Seahorse max size: 20cm/8in		One of the underappreciated beauties of the aquarium hobby, it is not often kept. Characteristic traits include thick body and tail rings and a very narrow body. A prominent coronet and eye spines are also associated with the species. Color is usually pale yellow or brown with contrasting dull spikes. Rarely is found in other colors, but may range from orange to purplish. 16-20 dorsal rays and 11 body rings.	Hippocampus barbouri, which has similar snout patterning, although subelongatus generally lacks developed spines and has a much higher coronet.

Hippocampus zosterae Dwarf Seahorse max size: 5cm/2in		A very commonly-kept species, it can be kept with little maintenance. It is the only species able to survive solely on artemia. Identification is unmistakable due to size and proportion of body parts. Color can range from white to greenish, often with some degree of mottled black or white patterning. 12 dorsal rays and 9-10 body rings.	Hippocampus bargibanti due to confusion over their common names.

Reference: Fishbase.org