How to Care for Seahorses 101 (2024 Complete Care Guide)

Featured Image - Seahorses
Featured Image – Seahorses
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: May 6, 2024
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If you’re thinking about getting a seahorse and wish to acquire more knowledge about their upkeep, you’ve come to the correct place! Seahorses, with their miniature size and distinctive physique, could arguably be considered one of the most captivating species of fish to introduce into a saltwater aquarium.

Article Summary

  • Seahorses are used in traditional Chinese medicine to treat ailments like pain, asthma, infertility, and baldness.
  • Seahorses prefer tall tanks, and water parameters should include specific salinity, temperature, and pH levels.
  • Seahorse owners should be diligent in monitoring their pets for signs of illness or distress.

I’ll be diving into everything you need to know about seahorses, including tank setup, diet, tankmates, and breeding…


All wild seahorse species live in shallow tropical and temperate coastal waters across the world. Four species are located in Pacific waters from North America to South America.

Cultural/Historical Significance

Seahorses are considered lucky and of good fortune to Torres Strait Island people.

They believe that seahorses are a symbol of both strength and power.

This fish is also edible and is quite a delicacy in China, Japan, Korea, and other Asian countries.


Additionally, seahorses have been used in Chinese traditional medicine for a long time.

They are believed to treat ailments like pain, asthma, infertility, and baldness. 

As the demand for seahorses is so high (over 150 million are used in the traditional medicine trade each year alone!), many seahorse species worldwide are categorized as vulnerable.


The Seahorse has even found its way into the gaming world!

A Sea Horse inspired creature called Horsesea is present in the video game Pokémon.

The Horsea pokémon is light blue with red eyes and a long, tubular snout.

Natural Habitat

Wild seahorses are typically found in sheltered areas like coral reefs, mangroves, seagrass beds, and estuaries.

They particularly like to swim among seaweed and other plants.

Tail Function

Their curled tail is able to grab onto objects such as plants, which is useful for when they want to anchor themselves to vegetation. 

Seahorses swim in an upright position and move forward through the water by using their dorsal fin.

They move up and down by adjusting the volume of air in their swim bladder.

How Do You Tell If They Are Male or Female?

Figuring out whether a Seahorse is male or female can be a simple process or it can be a difficult one.

For example, juvenile (young) and subadult seahorses, as well as virgin males that are not in breeding condition are very hard to sex. Most are mistaken for females.

Mature Seahorses

However, sexing entirely mature seahorses that are in breeding condition is often straightforward.

Male seahorses have a brood pouch underneath their abdomens at the base of the tails. Female seahorses don’t have a brood pouch. 

You will be able to see this difference more clearly if your seahorses are courting or breeding as males engage in vigorous pouch displays.

This performance entails inflating the pouch with water, making it almost impossible to misidentify.

Seahorse Hitched To a Plant

On Some Occasions

While most mature seahorses are easy to sex, occasionally, it can be hard to tell whether they are male or female.

Many factors can contribute to misgendering. 

For example, some virgin male seahorses have pouches that shrink to a very small size during off-seasons, making them hard to spot.

Alternatively, some mature females even possess a pseudo-pouch.


Wild seahorses are usually yellow, pink, gray, white, or orange.

While they’re not the most vibrant fish species, they definitely pack a punch in the unique factor. 

One of the most interesting aspects of seahorses is that they are able to change their color to help them blend into their surroundings.

This is called habitat mimicry or crypsis and is an invaluable tool in the wild.

Protection From Danger

As seahorses are extremely poor swimmers, they are unable to outswim predators or protect themselves from danger.

Instead, they mimic the color of their environment to make them less noticeable.

This allows them to feed and go about their business without being instantly spotted by predators.


Additionally, seahorses change color during courtship to communicate a willingness to mate and reinforce their bond. Both male and female seahorses change color during courtship.

How Big Do Seahorses Get?

Most seahorse species are small, but some can grow relatively large.

They range from 0.6 inches to 14 inches in size.

The smallest species of seahorse in the world is the Satomi’s pygmy seahorse (Hippocampus satomiae), which grows to a minuscule 0.6 inches. 

The largest seahorse species in the world is the big-bellied seahorse (Hippocampus abdominalis), which grows to around 14 inches in length.

Habitat Mimicry

Do Seahorses Have Male and Female Parts?

Seahorses don’t have male and female parts as such, but their parenting roles are reversed.

Male seahorses have pouches where they raise their offspring after mating with a female.

In fact, they are the only animals in the world in which the males bear the young. 

All male seahorse species have pouches, but some species of Syngnathidae don’t.

In these varieties, the female’s eggs attach to the male’s body’s surface rather than the brood pouch.

Do Seahorses Mate for Life?

Unlike many species of fish, most species of seahorses are monogamous and mate for life.

As the seahorse is a poor swimmer and spends most of its time in camouflage to hide from danger, finding a mate can be rather tricky.

By finding a mate for life, male and female seahorses can go through more pregnancies during a single mating season.

This increases their chances of successful reproductions. 

Monogamous seahorses who have paired off reinforce their bond by participating in daily greetings. 


Pair-bonded seahorses often decline and go through a state of depression when they lose their mate. Widowers have been known to grow lethargic and lose their appetite.

Why Do Male Seahorses Get Pregnant?

It’s not clear why male seahorses get pregnant and give birth instead of females. They are the only animals in the world that this occurs in. 

Why Are Male Seahorses Considered Male?

Although male seahorses carry and give birth to their young, they are still classed as male as they are the gender that produces sperm.

In biological terms, the male sex produces smaller reproductive cells called sperm.

Biological males of a species are considered male when they fertilize eggs, while biological females of a species are considered female when they produce eggs.

The fact that a male seahorse is the one who gives birth to the offspring doesn’t come into the equation as it still produces sperm.

Male Seahorse Body

Does a Seahorse Die After Giving Birth?

A seahorse doesn’t die after it has given birth. In fact, seahorses mate a considerable number of times during a single mating season to increase their chances of successful reproductions. 

Are Seahorses Poisonous to Eat?

Seahorses are not poisonous to eat.

They are a popular food in China, Korea, Japan, and other Asian countries.

They are often served deep-fried on skewers in street markets.

Types of Seahorses

There are around 36 seahorse species, all of which range in size and color. Let’s take a look at some of the most common species found in the fishkeeping hobby. 

Aquarium Varieties

  • Brazilian Seahorse (Hippocampus Reidi)
  • Gorgonian Pygmy Seahorse (Hippocampus Bargibanti)
  • Dwarf Seahorse (Hippocampus Zosterae) 
  • Lined Seahorse (Hippocampus Erectus)
  • Tiger-Tail Seahorse (Hippocampus Comes)
  • Smooth Seahorse (Hippocampus Kuda) 
  • Igen’s Seahorse (Hippocampus Ingens)
  • Barbouri Seahorse (Hippocampus Barbouri)

There are many other species of seahorses, though not all of them are commonly found in the hobby nor are suitable for home aquariums. 

The short-snouted seahorse and long snouted seahorse, for example, are not suited for aquarium life.

Maintenance and Care

In this section, I’ll explain the type of care and maintenance that goes into keeping seahorses.

As seahorses come from the ocean, they are a marine species of fish.

Saltwater tanks are a bit more complicated to set up and maintain than coldwater or freshwater aquariums.

I’d advise setting up either a freshwater or coldwater aquarium first before you start a saltwater tank.

Can You Raise a Sea Horse in Captivity?

Seahorses can be raised in captivity and are not overly challenging to breed.

A lot of species of seahorse available to purchase are captive-bred, though some specimens may be from the wild.

Seahorse Anchored to a Plant
Seahorse Anchored to a Plant

Are Seahorses Hard to Take Care Of?

Seahorses are not usually too challenging to take care of as long as their aquarium is suitable, and their needs are being met.

However, they do have quite specific care and dietary requirements that I’ll go into detail about later on.

What Is the Lifespan of a Seas Horse?

Seahorses usually live for around 4 to 8 years, though most live for 5 years.

A wild seahorse has a considerably shorter lifespan of just 1 to 4 years.

Larger species like the Mustang seahorse and Sunburst seahorse can even live for up to 10 years!

Do They Die Easily?

If their tank is unsuitable and their needs are not being met, a seahorse can succumb quite quickly.

This is heightened by their lack of scales (they are a scaleless fish), which makes them susceptible to disease, illness, and infections.


A seahorse is quite a picky eater and has specific dietary requirements. If they don’t get the right sort of food, then they can die of starvation. 

How Much Does It Cost to Own a Seahorse?

A seahorse is not a cheap pet.

The fish itself is often over $50, with rarer species being costlier. You’ll also need a tank, aquarium equipment (like filter, heater, and lights), accessories and decor, food, medicine, and much more.

All of these components quickly drive up the cost of owning a seahorse.

Compared to freshwater and coldwater tanks, marine aquariums are a lot more expensive to set up.

What Do They Eat?

Due to how slowly seahorses swim, eating can be quite challenging for them.

To complicate things even more, seahorses don’t have stomachs.

This means they need to eat constantly as food passes through their digestive system very quickly.

An adult wild seahorse will often eat 30 to 50 times a day.

A baby seahorse eats a staggering 3,000 times a day.

How Do Seahorses Eat?

All seahorse species have no teeth, so they feed by sucking up food and swallowing it whole.

They primarily eat tiny fish, tiny crustaceans, and plankton in the wild.

The shape of a seahorse’s body and neck makes them efficient at catching prey.

Ambush Tactic

Seahorses will hover silently close to their prey, attached to coral or plants using their tails. 

They will usually change color to blend into their surroundings and to make them less noticeable to their prey.

When the seahorse is ready to strike, it will tilt its head and quickly slurp up its prey, which has a rather unique sound. 

The whole process allows them to simply wait for their prey to wander past their hiding spot instead of actively pursuing it.

This makes up for their poor swimming ability, which would make catching prey pretty difficult! 

What Is the Best Food for Them?

The best food for seahorses in home aquariums is live or frozen mysis shrimp.

You can also feed them brine shrimp, copepods, amphipods, and grass shrimp to make sure they get a varied diet.

How Should I Feed Them?

Dagger Grass Shrimp By Brian.gratwicke at English Wikipedia
Dagger Grass Shrimp By Brian.gratwicke at English Wikipedia

Seahorses are very slow feeders, so you’ll need to make sure they are getting access to enough food.

A lot of aquarists who own seahorses use a turkey baster or pipette to target feed them.

You could also hand feed them with some time and patience.

Other fishkeepers set up a feeding station for their seahorses.

Feeding Station

You could use an upturned clamshell or hollow out a little section of live rock for this purpose.

Every time you feed your seahorses, place their meal on the feeding station. 

It might take some time for your seahorses to learn this is the area where they get fed, but they should eventually associate the feeding station with food.


You can lure your seahorse to the feeding station with food using a turkey baster to help them get the gist of things. 

How Many Times a Day Should I Feed Them?

You should feed your seahorse twice a day, once in the morning and once in the evening.

Feed your seahorse between 6 to 8 mysis shrimp in one sitting. Larger species will need bigger portions of mysis shrimp.


The best type of substrate for a seahorse is sand.

As seahorses inhabit seagrass beds in the ocean, they prefer fine sand.

Live sand is a particularly good option as it is beneficial for stabilizing the water chemistry in your aquarium. 


Store-bought bags of live sand are safe for fish but avoid sand collected from the sea/ocean and other systems as they can carry harmful pollutants, parasites, or dangerous hitchhikers.


A good filter is key to a healthy aquarium as it helps keep your water clean.

While it’s important to select a powerful filter capable of cleaning your aquarium’s size, you have to make sure the flow rate isn’t too strong.

Seahorses are poor swimmers and can easily get sucked into the intake tubes of overly powerful filters.

This is especially true for smaller species like dwarf sea horses. 

Ideal Filters

Sumps, canister filters, sponge filters, and hang-on-back filters are all suitable for a seahorse aquarium.

Many models come with adjustable flow rate settings so you can tweak the flow rate and suction of the filter, too.


It’s a good idea to cover the intakes on hang-on-back filters or units with a lot of suction with (brand new) pantyhose or a fine-pored sponge to prevent casualties.

Installing spray bars or flow diffusers onto your filter can also help.


Wild seahorses come from tropical and temperate ocean waters worldwide, so they require heated water in a home aquarium.

To do this, you’ll need a fish tank heater.

You can use a few different types of aquarium heaters for a seahorse aquarium, but they all have the same function (i.e. heat your aquarium!).


In reef tanks, proper lighting is vital for the growth of plants and corals, as well as ensuring a natural day and night cycle for your seahorses.

A lot of aquarists keep their aquarium lights on for 8 to 12 hours each day. 

Aquarium Plants
Aquarium Plants

Plants and Decorations

A seahorse tank needs to contain a lot of hitching posts or thin decorations for them to wrap their tails around when they are resting.

Fake plants, live plants, dead coral, kelp, and mangroves are all good options.


Although you can add any marine species of plants you want to a seahorse tank, I personally like Merman’s Shaving Brush, Red Grape Kelp, and Caulerpa Prolifera.

They are great hitching posts for sea horses to anchor themselves to.

Corals like Gorgonians and Leather corals are also good options for a seahorse tank.

Bear in mind that seahorses will wrap their tails around almost anything, so some coral types might not be suitable for a seahorse tank.

What Size Tank Do They Need?

The majority of seahorse species need a tank that is at least 20 gallons or 30 gallons in volume. This is adequate for a pair of adult seahorses.

Larger seahorse species will need a bigger aquarium.

Seahorses prefer tall tanks, so try to go for one that has a lot of vertical height (minimum of 18 inches). The tank’s height needs to be at least 3 to 4 times the height of your seahorse’s adult size.

Housing Recommendations

Seahorses need specific water parameters and requirements in order to thrive, so you’ll need to ensure your aquarium accommodates their needs.

Water Requirements

Wild seahorses come from sea waters, so the water in their tank needs to have a suitable level of salinity.


Make sure the salinity of your seahorse’s water is between 1.020 and 1.024.

Water Changes

One of the essential features of a healthy reef tank is excellent water quality, which is achieved through good filtration and water changes conducted often.

If water isn’t removed from your seahorse tank regularly, ammonia, nitrite, and nitrate will quickly build up.

This can be extremely problematic for your fish and can result in sickness and even death.

Aquarium Water Bubbles
Aquarium Water Bubbles

Water Change Frequency

Most aquarists remove around 20% to 30% of the water each week (replenished with the same amount of water that is removed), but this depends on the size of your aquarium and the number of fish you own. 

If your aquarium is undersized and overstocked, then you will need to perform larger and more frequent water changes to keep your tank clean.


Seahorses are accustomed to tropical and temperate sea waters, which needs to be replicated in a home aquarium.

While seahorses require slightly cooler temperatures than the majority of other marine species, they still need relatively warm conditions between 71 and 76 ˚F.

Water pH Level

The majority of seahorses need their aquarium water with a pH level between 8.1 and 8.3.

However, check the pH preferences for the type of seahorse you want to get as some may have slightly different needs.


Aquarium fish, especially marine species, require a hefty amount of work.

Once you’ve set up a seahorse tank, you’ll need to conduct regular maintenance to keep your pet healthy.

Make sure your seahorses are getting enough to eat and ensure they get the right type of foods. It’s also important to frequently check your fish over for signs of illness or disease.


Alongside these tasks, you’ll need to perform water changes, test your aquarium water frequently, and check your equipment for wear and tear signs.

Research First

If you’ve never owned fish before, I’d advise learning a little more about their care and maintenance to make sure they’re the right animals for you.

This is especially true for marine species like seahorses as their setups are a bit more challenging to run than freshwater or coldwater tanks.

Compatibility/Suitable Tankmates

Due to their passive nature and the fact that they don’t have any teeth, seahorses can make good additions to community tanks, provided the other fishes are equally as peaceful.

What Fish Can They Live With?

Seahorses can be kept with a wide range of fish as they are very peaceful animals.

When selecting tankmates for a seahorse, choose slow and passive species, and avoid aggressive fish species such as the triggerfish.


Some good options are Banggai cardinals, pajama cardinals, royal grammas, scooter blennies, small goby species, and firefish.

Can Seahorses Be Kept Together?

Seahorses can be kept together, but it’s best not to keep different species in the same tank.

Species from different parts of the world carry microfauna that they have an immunity to.

If they come into contact with a species that is not immune to this type of microfauna, it can wreak havoc on the other seahorse’s immune system.

Can Cause Illness

This can cause an array of issues, as well as make the fish more susceptible to other bacteria or illnesses that previously wouldn’t be harmful.

Seahorses are more prone to bacterial related problems than other species as they have a primitive immune system. 

Herd of Seahorses Hitched on a Coral
Herd of Seahorses Hitched on a Coral

How Many Should You Keep Together?

Seahorses prefer to live in pairs or groups, so it’s best to get at least 2 for your tank.

A pair of seahorses need a minimum of 20 to 30 gallons.

You’ll need to add on an extra 20 to 30 gallons for each additional pair of seahorses.

Unlike many other wild animals, a pair of males can be kept in the same tank without any issues.

Can I Keep Just One?

It’s not recommended to keep a single seahorse as they enjoy the company of other seahorses.

If you don’t keep seahorses in pairs or groups, they can get bored and depressed.


Seahorses are susceptible to stress and bacterial related infections. As they have no scales, they are more at risk of developing infections than other species.

That’s why it’s crucial you regularly check these aquatic pets for signs of illness or distress.

Signs of a Healthy Seahorse

It’s a good idea to check over your seahorse for signs of illness/disease or any other abnormalities frequently so you can detect when something is amiss. 

A healthy seahorse will be active, breathing calming, regularly ingesting food, and constantly moving their eyes.

Signs that might indicate a problem include cloudy eyes, marks, cuts, rapid breathing, lethargy, and faded coloration.

Red Flags

Identifying when your seahorse is unwell is vital for the right course of action and choosing the right medicine or treatment. General red flags of a sick sea horse include:

  • Poor appetite
  • Loss of color
  • Clamped fins
  • Cloudy eyes
  • Rapid breathing
  • Lethargy
  • Erratic swimming patter
  • Flashing
  • Inflammation
  • Red gills
  • Lesions
  • Frayed fins
  • Malnourishment

Why Are My Seahorses Turning Black?

One of the main reasons why fishes turn black or develop black spots is due to stress.

Your seahorse could be stressed for a few different reasons, including an incompatible tankmate, poor health, or a tank that is not big enough.

Why Are My Seahorses Turning White?

Fishes change to a white color usually when they are in poor health, stressed, or are dying.


If you notice your seahorse has had a change in color, then first check your water parameters to make sure everything is in order. 

High ammonia, nitrite, or nitrate levels can cause seahorses to lose their color, so you should do a water change immediately if this is the case.

If your water parameters are all in order, check your fishes over for illness or disease signs.

You should also watch their behavior to identify a bully or predator in your tank that is causing mischief.

Healthy Seahorse

Common Illnesses and Diseases

Fin/Tail Rot

Fin/tail rot is one of the most common diseases that affects marine, freshwater, and coldwater fishes.

Bacteria and fungi cause it, but it’s usually the former. This disease is linked to poor water conditions. 


Aggressive tankmates that are nipping or bullying your seahorses can also lead to fin rot.

The most common fin or tail rot symptoms are fraying or reddening fins/tail with brown or black edges.

Severe cases can lead to complete destruction of the fins or tail.

If left untreated, this disease can spread to your fish’s entire body and result in death.


The best way to treat this disease is to act quickly before the fins are overly damaged.

Antibacterial medicine should be used for bacterial fin rot, while antifungal medication should be used for fungal fin rot.

To ensure your seahorses recover fully, you will need to improve the quality of their water.

Marine Ich

Marine ich (also known as marine white spot disease) is another common disease you’ll likely run into when keeping seahorses and marine species. As seahorses are scaleless, this disease can be especially dangerous.

It’s caused by the parasite Crytopcaryon irritans.


The most obvious symptom of marine ich is white spots.

If your seahorse has marine ich, they will look like they’ve been sprinkled in salt.

These small white spots can appear on the body, fins, and gills of your seahorse.

Other common symptoms include flashing, rubbing against objects or decor, cloudy eyes, increased mucus production, pale gills, and changes in scale color or skin.


If your seahorse develops this disease, you’ll need to place them in a quarantine tank by themselves or with other infected fishes.

Formalin is one of the most popular treatments for external protozoans.

It’s most effective when used as a dip (check the manufacturer’s instructions before you do this).

Malachite green and methylene blue are other two effective treatments for external parasites.


It’s best to avoid treatments that contain copper sulfate as seahorses are very sensitive to the abrasive properties of metals due to their scaleless skin.

The male seahorse carries the eggs in its pouch for between 9 to 45 days before giving birth to fully-developed (albeit small) seahorses.

Once the young have been released into the water, the male will mate again within a few hours or days during the mating season.

Courtship Rituals

Before seahorses breed, they engage in courtship that can last several days. Males and females often change color during this time.

They will swim side by side holding onto one another’s tails.

Alternatively, they might grab onto the same strand of seagrass with their tails and spin in unison (called a “predawn dance”).


The pair will eventually participate in a “true courtship dance” that usually lasts for 8 hours.

The male pumps water through his brood pouch which grows larger and opens up to show its emptiness. 

Once the female’s eggs mature, she will drift upwards with the male snout-to-snout and the duo will interact for roughly 6 minutes. 

The female swims away and returns the next morning at which point she will insert her ovipositor into the male’s pouch and deposit thousands of eggs.

As the female deposits her eggs, her body slims while the male’s grows. The pair drop to the sea bottom and then the female swims away.

Can They Breed in Captivity?

Seahorses breed quite easily in captivity.

A pair of mated seahorses will often reproduce with little intervention.

However, the challenge lies with raising seahorse fry.

Seahorse Pair
Seahorse Pair

How Do I Get Them to Breed?

One of the most critical aspects of successfully breeding seahorses is good water quality.

This is especially important for the survival of seahorse fry. 

Make sure your mated pairs are fed 2 to 3 times a day using live or frozen foods like mysis shrimp and other small crustaceans.

Offer them a varied diet to ensure they get enough nourishment.

Undernourished pairs don’t usually reproduce and, even if they do, defects can be present in the fry if the eggs and embryos didn’t get the right nutrients.


While seahorses can breed in community tanks, it’s best to go for species-only setup that can accommodate 2 or 3 pairs as they might be outcompeted for food.

Looking After Fry

Once your seahorses have successfully mated, you do not need to remove the pregnant male. Males usually give birth to the fry in the early morning.

Fry are born individually or in small groups.

They look like mini versions of adult seahorses.

Fry are phototropic, which means they swim directly to light at the surface of the tank to swallow air through their mouth to fill up their swim bladder, which then seals up.

Getting Tangled Up

Wild seahorse fry will separate immediately once they reach the surface, but captive-bred fry will often get tangled up in a huge mass of other fish.


Make sure you break up the masses before the fry becomes overly stressed and use too much energy trying to swim away.

You can place the young in groups of around 30 to 40 in small tanks like 5 gallons.

Seahorse fry don’t eat for a few hours after being born.

Feeding Seahorse Fry

After between 18 to 20 hours, the fry will begin to look for food.

This is where the process gets tricky as seahorse fry have very complex dietary needs.

The fry are fed in 3 main stages by: 

  1. Culturing microalgae as food for zooplankton
  2. Culturing zooplankton (normally Branchionus rotifers) to use as their initial food\
  3. Eventually weaning them onto newly-hatched brine shrimp.

At roughly 8 months old, the young seahorses will be ready to move into a tank with their parents and other adult seahorses.


Summing Up

The seahorse is a truly fascinating and unique aquatic pet, so they’re well worth considering for your saltwater tank.

They are available in a variety of colors and species, ranging from the very miniature to extremely large. 


They need to be fed a diet that mainly consists of mysis shrimp, though other foods like brine shrimp, copepods, and glass shrimp can also be offered.

Tank Size

Most types of seahorse need to be kept in tanks no smaller than 20 or 30 gallons in size. They prefer to be kept in pairs or groups as they enjoy the company of other seahorses.

You can also keep them in community tanks as long as you select appropriate tankmates. 

Seahorses are monogamous and mate for life. They breed easily in captivity, but raising the fry can be difficult. 

If you fancy a bizarre but equally adorable fish that’s interesting to watch, then look no further than the seahorse!

Thanks for taking the time to read! If you found the information useful. Feel free to share this guide with your friends and loved ones.

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