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Lined Seahorse

Hippocampus erectus

AnimaliaChordataActinopterygiiSyngnathiformesSyngnathidae

📍 Atlantic Ocean, Nova Scotia to Caribbean

Ask Finn

Atlantic seahorse available as captive-bred specimens that are far hardier than wild-caught. Males brood young in a pouch. Requires a species-only tank with slow flow, hitching posts, and multiple frozen mysis feedings per day.

Size6"
Min Tank30g
School2+
peaceful
Zonemid

Care Guide

Diet

Lined seahorses are obligate carnivores requiring multiple daily feedings of frozen mysis shrimp, their primary diet. Feed small portions once daily, as they have limited stomach capacity and slow metabolisms. Occasionally supplement with frozen copepods or enriched brine shrimp to provide nutritional variety.

Behavior

Lined seahorses are sedentary, slow-moving fish that spend most of their time anchored to seagrass, coral, or hitching posts using their prehensile tails. They are peaceful and non-aggressive but can be outcompeted for food by faster swimmers. Males exhibit unique brooding behavior, carrying fertilized eggs in a specialized pouch until they are fully developed.

Breeding

Breeding captive-bred lined seahorses is possible but challenging and rarely successful in home aquariums. Pairs require pristine water conditions, abundant live food, and minimal disturbance to form bonds and reproduce. Fry are extremely difficult to rear due to their tiny size and specific dietary requirements.

Common Diseases

Vibrio Infection (Bacterial)

Symptoms

Lethargy, loss of appetite, discolored patches on body, curved posture, rapid decline

Treatment

Improve water quality immediately, perform 25% water changes daily, consider antibiotic treatment if available; prevention through pristine conditions is critical

Pouch Infection (Males)

Symptoms

Swollen or discolored brood pouch, reluctance to move, inability to release fry, male death if untreated

Treatment

Maintain excellent water quality and low bioload; antibiotics may help if caught early; prevention through stress reduction is essential

Parasitic Copepods

Symptoms

Visible parasites on body, scratching against objects, lethargy, weight loss

Treatment

Freshwater dips (brief, 2-3 minutes) may help; improve water quality and increase feeding; copper-based treatments should be avoided as seahorses are sensitive

Nutritional Deficiency

Symptoms

Curved spine, poor coloration, lethargy, inability to maintain upright posture

Treatment

Ensure varied diet of quality frozen mysis shrimp and enriched foods; supplement with vitamin-enriched preparations; feed multiple times daily

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Quick Facts

pH
8.1–8.4
diet
frozen mysis shrimp
maxSize
6 inches
salinity
SG 1.020–1.025
minTankSize
30 gallons tall
temperature
68–77°F (20–25°C)

Temperature

68–77°F

20–25°C

Stats

Community tips0
Kept by0 hobbyists