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Not furry, but we like them anyway.

Lined Seahorse

Hippocampus erectus Perry, 1810

Also called Northern seahorse, Spotted seahorse

SpeciesShort profile

From Western Atlantic, from Nova Scotia to Venezuela and Brazil, including the Gulf of Mexico, the Caribbean and the US east coast. Aquarium fish are usually captive-bred.123

At a glance the quick version

Length12 to 19 cm123
Lifespan1 to 4 years2
Sizesmall

Adults usually 12 to 17 cm; maximum recorded about 19 cm.

One to four years in the wild; around four years is typical in captivity.

Gentle and peaceful
Lifelong pair bonds with morning greeting dances
Wide range of colours
23

Looks how to spot one

Bony-plated seahorse

An upright seahorse whose body is armoured in roughly fifty bony plates. Fine white lines trace the neck and tiny white dots speckle the tail, and a crown-like coronet tops the head. Colour is highly variable and adapts to its surroundings.23

ColoursGreyBlackRedGreenOrangeYellow2

Personality what they are like

Peaceful and unhurried. Pairs bond for life and renew their bond each morning with a short dance, and they make soft clicking sounds with the coronet.23

Daily activity how busy a day looks

A slow, upright swimmer that beats its small fins very quickly and spends most of its time anchored by its prehensile tail to grasses and other holdfasts.23

Grooming and care the hands-on bits

Rated difficult. It needs calm, clean water, several small meals a day and prompt removal of leftover food. Captive-bred fish already eat frozen foods.32

Home where they are happiest

A tall species aquarium (at least about 40 cm high) of about 115 litres (30 US gallons) for a pair, with gentle flow and plenty of hitching posts. Water about 20 to 26 °C, pH 8.1 to 8.4, dKH 8 to 12, specific gravity 1.020 to 1.025.32

Food basics what goes in the bowl

Small crustaceans such as frozen mysis shrimp, offered two or more times a day. It suction-feeds through its long snout.321

Company who they like around

Best kept as a mated pair or a small group of its own kind in a species-only tank, away from fast or boisterous fish.32

The story where it all began

George Perry described the species in 1810. It is the only seahorse native to Chesapeake Bay, and it has been bred in captivity for many years, supplying most aquarium fish.21

Fun facts for the dinner table

  1. 1

    Each coronet is unique, a little like a human fingerprint.2

  2. 2

    The male carries the eggs in a pouch under his tail for about 20 to 21 days.1

  3. 3

    A single male can carry around 650 eggs.2

  4. 4

    Its fins beat about 20 to 30 times per second.2

  5. 5

    It is the only seahorse species native to Chesapeake Bay.2

Recognised by the official bits

IUCN Red List
Vulnerable (assessed 3 October 2016)1
CITES
Appendix II1
Taxonomy
Family Syngnathidae; described by George Perry in 18102

The care rhythm a typical week and year

A typical home-care rhythm for a Lined Seahorse. A starting point, not a vet's advice.

Owner questions the things everyone asks

How often should I feed my Lined Seahorse?

Feed your lined seahorse two or more times a day with small amounts of frozen mysis shrimp. Furry Diary's starting plan is to offer small amounts once or twice daily, and it's important to remove any uneaten food promptly to keep the water clean.321 Pet Wiki plan

What does a Lined Seahorse eat, and what should it never eat?

Your lined seahorse eats small crustaceans like frozen mysis shrimp, which it suction-feeds through its long snout. It should never be given large or live foods that could harm its delicate digestive system, and always avoid any food not specifically recommended for seahorses.321

How much space does a Lined Seahorse need?

A pair of lined seahorses needs a tall aquarium of at least about 115 litres (30 US gallons) with a height of around 40 cm. The tank should have gentle water flow and plenty of hitching posts like seagrasses for them to anchor with their tails.32

What temperature, light or water does a Lined Seahorse need?

Keep the water temperature between 20 and 26 °C, with a pH of 8.1 to 8.4, dKH of 8 to 12, and specific gravity of 1.020 to 1.025. Furry Diary's plan suggests checking temperature daily and salinity weekly, and using only fresh RO water for top-ups.32 Pet Wiki plan

How often should I clean a Lined Seahorse's home?

Furry Diary's starting plan recommends a weekly glass cleaning and a 10 to 20% water change every two weeks. Promptly remove any leftover food after each feeding to maintain the calm, clean water they need.32 Pet Wiki plan

Can a Lined Seahorse live with others?

Lined seahorses are best kept as a mated pair or a small group of their own kind in a species-only tank. They should not be housed with fast or boisterous fish, as they are peaceful and unhurried swimmers.32

How long does a Lined Seahorse live?

A lined seahorse typically lives between 1 and 4 years. Providing calm, clean water and a proper diet can help them reach the upper end of that range.2

Can I handle a Lined Seahorse?

Handling a lined seahorse is not recommended, as they are delicate bony-plated fish that can be easily stressed or injured. It's best to observe them peacefully in their aquarium and avoid any physical contact.32

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

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Where this comes from

Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.

  1. FishBase: Hippocampus erectus summary fishbase.seused for distribution, depth, length, gestation, IUCN and CITES status, captive rearing
  2. Wikipedia: Lined seahorse en.wikipedia.orgused for names, description, colours, behaviour, lifespan, reproduction, fun facts
  3. LiveAquaria: Lined Seahorse, Captive-Bred liveaquaria.comused for aquarium care level, tank size, water parameters, diet, tankmates

Checked 2026-09-30. Text is written in our own words from these sources.