A common misconception about seahorses regards their color. The color of a seahorse is NOT fixed and changes based on mood, surroundings, lighting, diet, age, varies with species, and many other factors. Seahorses are masters of camoufletage.
Seahorses have been around for over 500 million years, but they’re not as old as you might think. In fact, the oldest known fossilized seahorse was only discovered in 1999. This particular specimen lived during the Cretaceous period (145 to 65 million years ago).
It was found by scientists in Germany who were looking at ancient sea beds for evidence of life from that time. The fossilized remains of this creature had been encased in rock since it died. They were able to determine its size and shape because the seahorse’s bones remained intact.
Seahorse mating and birth
Seahorses are born life, but they don’t stay that way very long. Most hatchlings are no bigger than a grain of rice, but some grow up to be as big as your thumb. Their tiny size makes them easy prey for larger fish like sharks and turtles.
Seahorses mate in the springtime. Male seahorses release sperm into the water, where females wait patiently for it. After fertilization takes place, the eggs float free until they hatch.
They lay their eggs in holes dug in sand or gravel bottoms. The young seahorses begin swimming away from the parent as soon as the eggs hatch. By the time they reach the ocean floor, they’ve grown legs and become fully independent.
According to Chris Crippen, the Virginia Living Museum’s senior director of conservation and animal welfare, the baby seahorses are fully formed but tiny less than a half-inch long and can’t swim very well or hold onto anything, so they just float in the water column.
During their mating ritual, male and female seahorses court by mirroring each other’s movements. Once aligned, the female gives the male the eggs and he either keeps them in his pouch or on a spongy area on his tail.
That’s right — the males carry the babies. A female can produce up to 1,500 eggs at once, with smaller species producing more eggs. The young are born live and must immediately fend for themselves. A minimal number (about 1 percent) reach maturity and have young of their own. Gestation ranges from two to nine weeks and is often fastest in warm water.
Seahorses have neither teeth nor a digestive system, which means they have to feed frequently. When they eat, they swallow their food whole. Typical prey is small guppies, small brine shrimp, crustaceans, and plankton.
When seahorses first appear out of the water, they look just like any other fish. But if you watch closely, you can see that they have two dorsal fins instead of one. These are used to help steer the seahorse through the water.
The body of a seahorse consists of an upper part called the head and a lower part called the tail. The head has three eyes: One large eye in front, another smaller eye above it, and the third eye below it. The mouth is located between these eyes.
The seahorse’s tail is made up of several soft segments that move independently of each other. Each segment contains a nerve cord along which sensory organs run. At the end of the tail is a fin that helps the seahorse swim forward.
A seahorse’s skin is covered with bony plates. These plates give the animal protection against predators and also allow it to camouflage itself when it wants to hide. Some seahorses use their armor to create patterns or designs on their bodies.
A seahorse’s teeth are small and sharp. It uses these teeth to cut into plants and algae so that it can get enough food to eat.
Like all fish, seahorses breathe through gills. Gills are located near the top of their heads. When a seahorse breathes, special cells lining its throat expand and contract, pulling oxygen-rich water into its lungs.
Seahorses spend most of their lives underwater, but they come to the surface to take a breath every now and then. They open their mouths wide and stick out their tongues to catch insects floating past during this brief moment.
Seahorses usually live about 20 years. However, there are some species that live longer. For example, the Chinese seahorse (Hippocampus Chinensis) grows up to 50 years old!
Scientists believe that seahorses evolved from ancestors that lived more than 200 million years ago. This theory is based on fossils found in rocks dating back to that period.
Discover the 10 Largest Seahorses in the World!
Seahorses are truly unique aquatic creatures with a head like a horse, a tail like a monkey, and a pouch like a kangaroo. There are nearly 50 species scattered throughout the globe, and they come in a variety of shapes and sizes.
They inhabit coastal regions all over the world, running the gamut from only .8-inch (2 cm) long (the pygmy seahorse) to 14 inches (35 cm) long (the big-bellied seahorse).
These tiny fish are not particularly talented swimmers but can use their tails to anchor to vegetation when the ocean gets rough. Seahorses move by using a small fin on their backs and an even smaller set on the back of their heads that controls steering.
Similar to a chameleon, seahorses are able to move each of their eyes independently and change their body coloration to match their environment. With such variety amongst the species, it’s helpful to organize them by attributes, like their maximum observed length. So, without further ado, let’s look at the top 10 largest seahorses in the world!
10. Short-snouted Seahorse and Barbour’s Seahorse (up to 15 cm, 5.9 inches)
Coming in at number ten, we have a tie between the short-snouted (Hippocampus hippocampus) and Barbour’s seahorses (Hippocampus barbouri), each capable of growing up to 15 cm long. The short-snouted seahorse lives in a preferred habitat of shallow muddy waters, estuaries, or seagrass beds.
They were endemic to the Mediterranean Sea and small parts of the North Atlantic, although a colony was discovered in the River Thames near London, England, in 2007. The bodies of the short-snout can be black, purple, orange, or brown.
The Barbour’s seahorse is the only species located entirely in southeast Asia, being native to the Philippines, Malaysia, and Indonesia. It is identifiable due to the zebra-striped pattern along its snout and its bright yellow coloration. The females are slightly smaller than the males.
9. Spiny Seahorse (up to 17 cm, 6.69 inches)
The spiny seahorse (Hippocampus histrix) is relatively rare but widespread throughout the Indo-Pacific region. They have been reported in Australia, Indonesia, Papua New Guinea, New Caledonia, and Japan. Unlike other species, the spiny seahorse can be found in deeper waters down to nearly 100 meters below the surface. The snout is very long and tapered when compared to the short-snouted, and coloration varies depending on the immediate environment.
8. Hippocampus reidi
Slender Seahorse (Hippocampus reidi), a species also known as the long snout seahorse. The female slender seahorse, like the one shown here, is yellow, while males are usually orange.
The slender seahorse has been found at a variety of ocean depths up to 55 meters below the surface of the water. They are native to many countries, including the US, China, Bahamas, Belize, Bermuda, Brazil, Colombia, Venezuela, Haiti, Jamaica, and Panama.
The slender is a subtropical seahorse and is in danger of becoming endangered in China and Brazil because they are used in traditional medicine and for commercial extraction. Males are usually a vibrant orange color while females are yellow.
7. Tiger Tail Seahorse (up to 18.7 cm, 7.36 inches)
(Hippocampus comes) in waters off Southeast Asia
Taking the number seven spot on our list, tiger tail seahorses (Hippocampus comes) can grow to nearly 19 cm and are found in Malaysia, Singapore, Thailand, Vietnam, and the Philippines. They can be identified by their alternating yellow and black stripes. The tiger tail is nocturnal and lives anywhere between 1-5 years long in the wild.
6. Lined seahorse
The lined seahorse is listed by the World Conservation Union (IUCN) Red List as “Vulnerable” due primarily to indirect evidence that numbers are continuing to decline, which has raised concern.
It was first described in 1810 by Perry as Hippocampus Erectus.
The lined seahorse sports a broad color spectrum to match its surroundings and often has white lines outlining the neck area, which led to its name.
They occur at depths from 2-230 feet (.5-70 m) and is often observed clinging to aquatic vegetation including mangroves, seagrasses, sponges, corals, and floating sargassum.
The basic color of the lined seahorse varies from gray, orange, brown, yellow, and red to black while brown specimens tend to be paler on their front side.
5. Long-snouted Seahorse (up to 21.5 cm, 8.46 inches)
(Hippocampus guttulatus) in the Mediterranean Sea
A shallow water dweller, the long-snouted seahorse (Hippocampus guttulatus) lives in coastal waters between 1-20 meters deep.
These sit-and-wait seahorses, suck their prey into their toothless mouth at the end of their long snout.
They are found in the Northeast Atlantic Ocean and the Mediterranean Sea. They have a horse-like head and a prehensile tail. They are usually around 12 cm long but have reached a maximum length of over 21 cm.
The long-snouted seahorse varies in color from dark green to yellow-brown, with small white dots speckled across its body. This seahorse species is relatively rare, and not enough data exists to make an accurate assessment of their conservation status.
4. Flat-faced Seahorse (up to 22 cm, 8.66 inches)
(Hippocampus trimaculatus)can grow close to 9 inches in length
This species is found primarily in shallow seas around Australia and Asia. Living up to its name, the flat-faced seahorse (Hippocampus trimaculatus) is typically flat, with eye spines, a narrow head, and no nose spines. The coloration can be golden orange, sandy-colored or black. Occasionally, brown and white zebra-like stripes have been observed on flat-faced seahorses.
3. Great Seahorse (up to 28 cm, 11 inches)
(Hippocampus kelloggi) on an isolated background
Squeezing in at number three on our list is the great seahorse (Hippocampus kelloggi). The great seahorse is difficult to identify because it shares a lot of characteristics with other species. However, subtle differences give it away, like its unusually high tail rings on tails which take up nearly 60% of its body. The great seahorse is usually a paler color and lives in the Indo-Pacific region with documented observations from the coast of East Africa to Japan.
2. Pacific Seahorse and Yellow Seahorse (up to 30 cm, 11.8 inches)
(Hippocampus ingens) clinging with its tail.
The silver medal for longest seahorse goes to two species, the Pacific seahorse (Hippocampus ingens) and yellow seahorse (Hippocampus kuda). True to its name, the pacific seahorse is the only seahorse to be found specifically in the eastern Pacific Ocean.
Like other species, the pacific seahorse can be a few different colors like green, brown, maroon, gray, and yellow. Males can be differentiated from females because of their keel, which is a strengthening ridge at the base of their tail resembling the keel of a boat.
The yellow seahorse, also known as the common seahorse, is native to the Indo-Pacific and has been spotted off the coasts of more than twenty countries. It is one of the most common seahorses to be found in residential aquariums and differs from other species because it features low, rounded bumps instead of spines along its body. Generally, the yellow seahorse averages between 7 and 17 cm but has been observed at a maximum length of 30 cm.
1. Big-belly Seahorse (up to 35 cm, 13.78 inches)
(Hippocampus abdominalis) has a name that says it all. They’ve got big bellies!
The big-belly seahorse(hippocampus abdominalis)is the largest seahorse in the world and can grow to more than a foot in length. Not only are they the longest measured seahorse variety, but the big-belly is also a relatively proficient swimmer, unlike the rest of the entries on this list.
The big-belly seahorse is found primarily along the coast of Australia and New Zealand, and has a long snout, obvious but narrow potbelly, and a long, coiled tail. The big belly appears in brown and yellow with a few darker splotches, while the tail is often circled with yellow bands. During mating rituals, both the male and female are capable of changing and accentuating certain colors.
More common seahorses
Here are some most common seahorses you might see when driving.
Common seahorse (Hippocampus kuda)
With a head that looks like a horse, a bumpy tummy, and a spiral tail, the common seahorse reaches a maximum length of 12 inches (30 cm). Males are larger than females. They come in a variety of colors, but the males are usually a bit grayer with dark spots.
The females often have some yellow and dark spots on their bodies. Each common seahorse has a crown on its head, as unique as a human fingerprint. Their bodies are quite smooth compared to other species of seahorses. You’ll find them in coral reefs in the Indo-Pacific in tropical water between 72 and 77 F (22 to 25 C).
As a result, the Common Seahorse, once plentiful, is now listed as a vulnerable species.
Pygmy seahorse (Hippocampus bargibanti and others)
Pygmy seahorses are about ¾-inch (2 cm) long. They are usually yellow, orange, pink, or gray changing color to blend in with their surroundings. They have a narrower snout than other seahorses and a prehensile tail to hold onto the fan corals they call home.
Some live on soft coral or among seagrasses as well. Pygmy seahorses live in larger groups than other seahorse species, gathering in numbers of up to 20 adults. You’ll find pygmies across the Western Pacific from Southern Japan to Northern Australia and out to the Solomon Islands and New Caledonia.
Pygmies are one of the most recently discovered species because they are so small. A scientist from New Caledonia, Georges Bargibant, discovered the species that was subsequently named for him accidentally while examining a gorgonian fan in the lab.
Leafy seadragon (Phycodurus eques)
As their name implies, leafy seadragons (or leafies) look like they have leaves attached to their bodies. Used solely for camouflage, the leafy protrusions help the animals look like bits of floating seaweed. They have both pectoral and dorsal fins and no prehensile tail. They typically grow to between 7.8 and 12 inches (20 and 30 cm) long.
Leafies are endemic to the ocean around Southern Australia, found only from Wilson’s Promontory in Victoria in the east, west to Jurien Bay, 140 miles (220 km) north of Perth in Western Australia. They inhabit temperate waters between 57 to 66 F (14 to 19 C), usually between 13 to 50 feet deep (4 to 15 m). Once you’ve spotted one, don’t worry about losing it — they move only about 1/8 of a mile (200 m) per hour.
Weedy seadragon (Phyllopteryx taeniolatus)
The weedy seadragon is equally as spectacular as its close relative, the leafy seadragon. Measuring between 12 and 15 inches (30 to 38 cm) long, they are camouflaged to blend into their surroundings as well, resembling weeds or seagrass. They are usually green or tan with many ridges and stripes and spots on their bodies. They have no prehensile tail.
You’ll find weeds only along the same southern Australian coastline as leafy seadragons, as well as in some areas in Tasmania.
How and why do seahorses change color?
All of the colors to which a seahorse can change are derived from three or four basic pigments contained in different chromatophores.
A yellow seahorse (Hippocampus kuda) has the ability to change color and do so for all sorts of reasons. Seahorses change color to mimic their surroundings when hiding from predators or prey (sudden, bold changes in appearance may even deter their enemies), and to communicate during courtship displays and territorial disputes.
They also may change color in response to environmental factors, such as temperature and lighting. Poor water quality and high levels of nitrogenous wastes (e.g., ammonia, nitrite, or nitrate) can cause chromatophores to contract and colors to fade.
While not unheard of in captive-bred seahorses, the bright red and orange coloration is seen in some wild seahorses likely is from natural sunlight, diet, or other factors.
When males are challenged by others of their sex, they’ll start flashing their brightest colors at each other to try to assert their dominance. They exhibit the same bold colors and behaviors when attempting to breed with females.
Like other fish, seahorses change color using small, sack-like organs known as chromatophores, which are embedded in their skin. They do have a base color and the colors they turn are based on that base color.
Each chromatophore contains one of three or four pigments. Expansion or contraction of the chromatophores via tiny muscles results in different colors being displayed with varying intensity.
Chromatophores are controlled in two ways: by the nervous system (when rapid camouflage is required for predator avoidance) and by hormones (during courtship and breeding).
Muscles attached to chromatophores can push pigment cells toward, or pull pigment cells away from, the surface of a seahorse’s skin. When the pigment is close to the skin’s surface, the animal’s color is brighter and more brilliant. In turn, when the pigment draws away from the skin’s surface, the resulting color is less saturated and somewhat dull.
In general, tropical seahorses tend to have brighter colors in their repertoire than temperate species.
Seahorse Diet and Conservation Concerns
All seahorse species described in this article are predators or omnivores. Due to their relatively inept swimming ability, they rely mainly on camouflage to catch their prey, which largely consists of small crustaceans, small shrimp, and planktonic organisms.
Seahorses do not have stomachs or teeth, instead of using their snouts to suck up desired prey. Due to simple digestive systems, they must eat fairly constantly to stay alive. Larger crustaceans, like crabs, rays, and certain fish are common seahorse predators.
Conservation data is limited because of the variety and relative rarity of many seahorse species. However, the primary threats to all seahorses are habitat loss, overfishing to support traditional medicine practices popular in countries like China, and commercial extraction for use as pets. To this end, twelve more well-known species are listed as vulnerable by the IUCN, and two are listed as endangered.
How to protect seahorses
The best way to prevent seahorse deaths due to human activity is to avoid harming them in the first place. Seahorses are very sensitive to stress, so if you see any signs of distress, it’s important to leave the area immediately.
If you’re planning on keeping a seahorse as a pet, keep in mind that the animals require a lot of space and attention. If you don’t have the time or resources to provide these things, then consider adopting an already existing seahorse rather than purchasing one.
If you want to help out seahorses in need, there are several organizations dedicated to protecting the creatures. The World Wildlife Fund has a list of recommended charities, including Sea Life Trust Aquarium, which works directly with wild populations of seahorses.