9 Things You Didn't Know About Seahorses

They're ridiculously bad swimmers that eat all the time.

Seahorse bodies are made of hard, bony plates instead of scales.

Laura Dinraths / Shutterstock

Seahorses are intriguing little creatures. They bob and drift in the water, awkwardly swimming while constantly eating, using their prehensile tails for courtship dances and to grip seaweed like an anchor so they don't go drifting away. They look sort of like horses, and really nothing at all like fish.

Their scientific name is hippocampus, which has roots in the Greek "hippo," meaning horse. Found in waters around the world, here are some interesting facts about these fascinating and unusual animals.

1. Seahorses Are Fish

Seahorses are fish and have many of the characteristics of their swimming counterparts, according to The Seahorse Trust. They live in the water and breathe through gills. They also have a swim bladder, which is an air-filled balloon-like organ that gives them buoyancy and helps them float.

Unlike any other fish, however, they have a flexible neck, a snout, and a nimble tail. They have that bendable tail instead of caudal fins. Caudal fins are the distinctive tails fins that fish use to propel themselves through the water.

2. They're Ridiculously Bad Swimmers

Seahorses propel themselves through the water by using a dorsal fin that beats from 30 to 70 times per second. But that tiny fin, plus an awkward body shape, doesn't make for easy going. As Ze Frank puts it in the video above, “Imagine trying to propel yourself on a skateboard solely by waving a Denny’s menu back and forth really fast.” In fact, seahorses can easily die of exhaustion when trying to navigate stormy seas, says National Geographic.

3. They Use Their Tails as Anchors

seahorse anchored with tail
Seahorses will use their prehensile tails to anchor themselves. ILEKI / Shutterstock

To avoid being swept away in turbulent waters, seahorses use their prehensile tails to grasp corals and sea grasses. The same trick helps them hide from predators. Interestingly, the seahorse's tail isn't round. It's actually composed of square prisms and covered in armored plates. A 2015 study published in the journal Science found that this shape is stronger and offers better functionality than a traditional round form. Researchers said that understanding the mechanics of the seahorse tail may help engineers develop seahorse-inspired applications in robotics, defense systems, or biomedicine

4. They Eat All the Time

long snout of seahorse
Seahorses use their long snouts to suck up food like a vacuum. Laura Dinraths / Shutterstock

Seahorses use their long snouts like vacuum cleaners, sucking in plankton and small crustaceans. The elongated snout lets them reach into tiny crevasses. It also expands and contracts, depending on the size of their meal.

Because seahorses don't have teeth or stomachs, eating and digestion is quite the chore. They have to eat constantly so they don't starve, reports the Oregon Coast Aquarium. They eat about 30 to 50 meals each day. A single seahorse can eat a whopping 3,000 or more brine shrimp every day.

5. They Take Courtship Very Seriously

When males are trying to catch the eye of a female, they lock tails and wrestle in an effort to try to impress her. Once a couple has paired off, the courtship gets even more intricate. They usually meet early in the morning when the female will venture into the male's territory for a date. They will change color (often matching) to show that there's mutual interest. The male will circle around the female and then they'll twist their tails together and pirouette in a slow dance that can last for hours.

6. Seahorse Males Take Care of Pregnancy

expectant male seahorse
An expectant father shows off his bulging belly. Sylke Rohrlach / Flickr

The seahorse is one of nature's best animal dads. After the elaborate dance above, the female deposits her eggs into the male's brood pouch. He fertilizes them and the eggs actually hatch inside his pouch. From there, the father maintains the correct level of salinity, getting them accustomed to what they'll have when they face the world. In some species, he might carry as many as 2,000 of them! Gestation lasts from 2 to 4 weeks and then the male has contractions, sending his fully formed mini seahorse newborns out into the sea.

7. They Use Color As Camouflage

seahorse blended into surroundings
Seahorses often blend in to match their surroundings. Suwat Sirivutcharungchit / Shutterstock

In addition to changing colors during their courtship dance, seahorses can turn different shades to blend into whatever is around them. They have special structures in their skin cells called chromatophores, says the National Oceanic and Atmospheric Administration (NOAA). These structures allow the fish to change colors to blend into their surroundings, protecting them from predators. They can remain unseen while they turn yellowish-green and cling on to a bit of seaweed. But they've also been known to turn a brilliant red in order to remain unseen in a pile of floating debris.

8. Newborn Seahorses Are Independent

When seahorse babies — called fry — pop out, they are utterly on their own. They swim away slowly, says the National Wildlife Federation, looking for something to hang on to. The bad news: Because of predators, fewer than one in 1,000 survive to adulthood. Others can't survive the strong ocean currents that carry them away from calmer areas where they can dine on microscopic organisms.

The babies that make it spend the first few weeks slowly drifting in the plankton of the ocean until they're strong enough to venture out farther on their own.

9. People Are a Big Threat

Captive-born seahorses are hardier in home aquariums than their wild counterparts. skynesher / Getty Images

Seahorses most often live in shallow waters near the coast, so human activities like pollution, fishing, and development have threatened their numbers. In addition, they are often captured to be used as pets in aquariums and for Asian traditional medicine. More than 150 million seahorses are taken from the wild each year for traditional medicine, according to the Seahorse Trust.

Wild-born seahorses generally don't fare well in home tanks. About 1 million are taken from the wild each year to be sold as pet, and it's believed fewer than 1,000 survive more than six weeks. However, their captive-born relatives are much hardier alternatives for people looking to have these unusual fish in their aquariums, says NOAA.

Save the Seahorse

  • Don't support the use of seahorses as medicine, which may kill more than 150 million wild seahorses every year, according to the Seahorse Trust.
  • Be very selective if you ever buy a seahorse as a pet. Make sure it was captive-bred and not one of the roughly 1 million taken from the wild every year.
  • Don't buy dead seahorses as souvenirs from gift shops. Another 1 million or so seahorses are taken from the wild every year to supply the curio trade.
  • Be a good tourist when visiting coral reefs, which are important habitats for many seahorses. And never litter in or near any ocean, since plastic debris and other trash can kill a wide range of marine animals, including seahorses.