TankBud

Horse hoof clam

Hippopus hippopus

Also known as Bear Paw Clam, Strawberry Clam, Hippopus Clam

SaltwaterClam

Horse hoof clam (Hippopus hippopus)
Frédéric Ducarme · CC BY-SA 4.0

Care at a glance

Temperature
75–81°F
24–27°C
pH
8.1–8.4
Adult size
11.8 in
30 cm
Minimum tank
40 gal
150 L
Temperament
Peaceful
Social behavior
Solitary
Swim level
Bottom
Diet
Photosynthetic
Difficulty
Medium
Breeding
Hard
Rarity
Common
Reef safe
Reef safe
Family
Cardiidae (Tridacninae)
Origin
Indo-Pacific, common around Indonesia and Palau and ranging from India to Kiribati

Overview

The horse hoof clam is a peaceful, reef-safe giant clam that rests on the open sand of a reef tank instead of on rock. It is best kept by someone with a little reef experience.

Did you know

The horse hoof clam has been fished hard as food across the Pacific and Southeast Asia, with its meat sold fresh in local markets. Trade pressure on other giant clams is mostly ornamental. For this one, subsistence harvest, more than the aquarium trade, is the main reason wild populations have crashed in several countries.

Caring for the horse hoof clam

Give a horse hoof clam moderately high, stable reef lighting. It is a bit less exacting than a maxima or crocea, but it still needs far more light than a low-light coral. Set it on a stretch of open sandbed rather than rockwork, with room to sit. It needs a tank of at least 40 gal (150 L).

Calcium, alkalinity and magnesium should stay elevated and consistent to support its notably thick, heavy shell. Keep calcium at least in the 380 to 440 ppm range, alkalinity at 8 to 11 dKH and magnesium at 1280 to 1350 ppm. The water should sit at 75 to 81°F (24 to 27°C) with a pH of 8.1 to 8.4.

The horse hoof clam hosts photosynthetic zooxanthellae and depends on them for most of its energy and shell-building. Juveniles under about 8 cm also benefit from a phytoplankton or greenwater supplement a few times a week.

Its flush mantle leaves less exposed tissue for mantle-nipping wrasses, crabs, shrimp and pyramid snails than a Tridacna clam does. It is not immune, so keep watching for them. Acclimate a new arrival slowly, floating it to match temperature and drip acclimating over an hour or more. Give it a lower-light spot for the first week or two before moving it into full light.

Good to know

Hippopus hippopus sits in the family Cardiidae, subfamily Tridacninae, in its own genus alongside just one other species. Its thick, heavily ridged shell carries the strawberry-red blotches behind its other common name, strawberry clam. The clearest way to tell it from a true Tridacna clam is the mantle. It stays flush with the shell margin and never overhangs the edge the way a maxima or derasa mantle does. It carries the same CITES Appendix II protection as every other giant clam. The IUCN lists it as vulnerable because of overharvesting across parts of its range.

In the wild

The horse hoof clam lives on shallow reef flats, seagrass beds and sandy lagoon floors across the Indo-Pacific, from India to Kiribati. It is most common around Indonesia and Palau. Juveniles briefly byssal-attach to solid substrate. Adults sit free in loose sand or rubble rather than staying fixed to rock the way most Tridacna do.

Common questions

What size tank does a horse hoof clam need?

A horse hoof clam needs at least 40 gal (150 L).

What temperature and pH does a horse hoof clam need?

A horse hoof clam is comfortable at 75–81°F (24–27°C) with a pH of 8.1–8.4.

What does a horse hoof clam eat?

A horse hoof clam lives mostly on the energy its zooxanthellae make from light. Juveniles under about 8 cm also benefit from phytoplankton or greenwater a few times a week.

How big does a horse hoof clam get?

An adult horse hoof clam reaches about 11.8 in (30 cm).

Related species