Eleotris marmorata Bleeker, 1852, Bandjarmasin, Borneo, and Palembang, southeast Sumatra, Indonesia.
OTHER COMMON NAMES
English: Marble goby, marbled sand goby; German: Marmorgrundel; Cantonese: Soon hock; Japanese: Kawaanago; Khmer: Trey damrei; Laotian: Pa bou; Malay: Bakutut, belantuk; Tagalog: Bia; Thai: Pla bu jak; Vietnamese: Cá bong.
The largest gobioid fish, this species may reach 35.4 in (90 cm) total length. Torpedo-like body shape with flattened head. Oblique, terminal mouth. Two dorsal fins and rounded caudal fin. Pelvic fins separate. Body brown with dark mottling giving a marbled appearance.
Southeast Asia in Laos, Cambodia, Vietnam, Thailand, Malay Peninsula, Sumatra and western Borneo. Also reported from Luzon (Philippines), and introduced into Taiwan for aquaculture.
Found in rivers, lakes, swamps, ditches, and ponds; water may be muddy or clear and over muddy, sandy, or gravel bottoms. This species may also be found in brackish waters around the mouths of rivers and canals.
Solitary, nocturnal hunter that prowls slow-moving streams, lakes, and swamps. During the daytime it rests at the bottom, taking cover among rocks, woody debris, or vegetation. This may be the typical behavior for most sleepers, hence the common name.
FEEDING ECOLOGY AND DIET
Predaceous; primarily eats small fishes, but also takes crustaceans, insects, and mollusks. Larval fish in culture ponds feed on cladocerans, rotifers, chironomids, and brachiopods.
Reach sexual maturity at approximately 3.9–4.7 in (10–12 cm) standard length. Spawns January through October. The eggs are about 0.09 in (2.3 mm) long and 0.02 in (0.63 mm) wide. Hatching starts at about 41 hours after fertilization, reaching its peak about 60–70 hours after fertilization. The males care for the eggs and guard the newly hatched fry. The larvae are initially pelagic but change to a more benthic habitat after about 25–30 days, becoming quite sedentary after about 40 days.
Not listed by the IUCN, but the species may be declining in some parts of its native range due to overharvesting.
SIGNIFICANCE TO HUMANS
A highly prized food fish in Southeast Asia, where it is also raised in ponds. In 2000, 277 tons (282 t) of marble sleeper were produced by aquaculture in Malaysia, Singapore, and Thailand. This quantity represents about 74% of the total global aquaculture of gobioid fishes for 2000, and had a value of about $1.2 million. In Borneo, marble sleepers captured for markets in Singapore and Japan may bring a fisherman $20 per lb ($10 per kg).