Dwarf seahorse (Hippocampus zosterae) care guide

Group
Marine fish
Family
Syngnathidae (seahorses and pipefishes)
Water
saltwater
Maximum size
5 cm
Temperature
20–24°C
pH
8.1–8.4
Hardness
Salinity SG 1.023–1.026
Minimum tank
40 litres
Care level
intermediate
Temperament
peaceful
Reef safe
with_caution

Care

Tank and decor: a very small seahorse best kept in a dedicated small tank with almost no flow, plenty of fine hitching posts (macroalgae, plastic plants) and filtration that cannot trap it, such as a sponge filter. Minimum tank: about 40 litres for a small group (an estimate based on its 5 cm adult size). Water: the list marks this species as subtropical. Our sources give no further figures, so the values here are general marine aquarium guidance, not species-specific: 20–24 °C, pH 8.1–8.4 and specific gravity 1.023–1.026. Seahorses are very sensitive to poor water quality and to bacterial infections, so keep the tank clean and well filtered. Identification: the list notes that it looks similar to H. reidi but is much smaller, with a maximum size of 5 cm. It is usually kept in small groups. All seahorses (genus Hippocampus) are listed on CITES Appendix II. In Great Britain, CITES Appendix II species are Annex B under the wildlife trade regulations, so sellers must be able to show the fish was legally imported or captive-bred and keep the paperwork. Captive-bred seahorses are strongly preferred: they settle better and usually accept frozen food. Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies). Checked October 2026.

Diet

Feeds on tiny live crustaceans. Unlike larger seahorses it is too small to take frozen mysis and is fed on live, enriched newly hatched brine shrimp several times a day, ideally from a hatchery running continuously. Copepods are also taken.

Breeding

As in all seahorses, the male carries the eggs in a brood pouch and later releases fully formed young; there is no further parental care. Pairs often greet each other with a daily courtship display. The fry are tiny and need live food such as rotifers, copepods or newly hatched brine shrimp, and are best raised in a separate tank. Our sources for this page give no further species-specific breeding details.

Compatibility and tank mates

Reef safe with caution: harmless to corals but easily eaten, stung or outcompeted. Keep in a species tank. Watch for hydroids and bristleworms brought in on rock or algae, which can harm it.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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