Horse's hoof clam (Hippopus hippopus) care guide

Group

Other invertebrates

Other names

Horse hoof clam, Strawberry clam, Bear paw clam, Hippopus clam

Family

Cardiidae (subfamily Tridacninae, giant clams)

Origin

Tropical Indian and Pacific Oceans, from India to Indonesia, Palau and Kiribati; sandy patches on shallow reefs and seagrass beds

Water

saltwater

Maximum size

45 cm

Temperature

24–28°C

pH

8.1–8.4

Hardness

SG 1.024–1.026, dKH 8–11

Care level

intermediate

Reef safe

yes

Flow

Moderate, indirect flow

Care

The horse's hoof or strawberry clam is a medium-sized giant clam, averaging about 22 cm and reaching about 45 cm. Its heavy, rhomboid shell has deep vertical ridges and strawberry-red blotches in bands. Its green-yellow mantle is narrower and less colourful than a Tridacna's, with tightly interlocking ridges. Light: it lives in shallow, sunlit water and gets about 65–70% of its food from symbiotic algae (zooxanthellae) in its mantle, so it needs very strong reef lighting. Place it on the sand bed in a bright spot, raising light gradually after purchase; a clam that gapes, shrinks back or bleaches is not coping. Set-up: unlike many Tridacna it does not bore into or attach to rock; it rests hinge-down on sand, so place it on a sand bed. A mature reef with stable calcium, alkalinity and magnesium, as the shell grows constantly. The water figures are typical reef-tank guidance rather than from a source. Pests and predators: check new clams for pyramidellid snails (tiny white snails around the hinge) and avoid angelfish, butterflyfish and some wrasses that nip mantles. Selling: giant clams are listed on CITES Appendix II. Captive-bred clams can be sold freely in the UK; imported clams must have been legally imported with CITES paperwork. It is listed as Vulnerable by the IUCN, overfished in many countries and possibly extinct in some, so choose aquacultured clams. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most other invertebrates. Never dose them in a tank holding this animal, and read the label of any treatment, fertiliser or algae remover before use. Sources: Wikipedia (en.wikipedia.org/wiki/Hippopushippopus). Checked October 2026.

Diet

Mostly fed by its zooxanthellae under strong light. It also filters phytoplankton and zooplankton: small clams get about 60% of their carbon this way and large ones about 34%, so smaller clams benefit from added phytoplankton. Nitrate and phosphate should be low but not zero.

Breeding

A protandrous hermaphrodite: it matures first as a male and later develops female organs. Spawning by one clam can set off others. Eggs and sperm are released into the water; the eggs stay viable for about 4–6 hours, the larvae swim in the plankton, then settle on sand, grow a foot and change shape after about 6–14 days, picking up their zooxanthellae after about 25 days. Rearing is done in aquaculture farms (for example in Micronesia), not in home tanks.

Compatibility and tank mates

Reef safe. Keep away from angelfish, butterflyfish, puffers, triggers and large hermits that pick at the mantle, and from corals that could sting it or shade it. Pyramidellid snails are a common pest of clams.

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