Armored stickleback
Indostomus paradoxus
FAMILY
Indostomidae
TAXONOMY
Indostomus paradoxus Prashad and Mukerji, 1929, Lake Indawgyi, Myanmar.
OTHER COMMON NAMES
None known.
PHYSICAL CHARACTERISTICS
Body elongate and slender, with a spatulate snout and terminal mouth. Eyes large and round. The single dorsal fin contains six rays, is located at mid-body length, and is preceded by five short and evenly spaced spines. The anal fin is opposite the dorsal fin, also with six rays. The caudal fin contains 11 rays and is rounded posteriorly. Pelvic fins are very small and thoracic, with only four rays. The precaudal tail region is very long and slender. Large pectoral fins have 23 rays. Body is covered by a complex armor composed of numerous plates. Coloration is a light brown, with numerous small, darker blotches and irregular stripes. Reaches 1.2 in (3 cm) in length.
DISTRIBUTION
Northern Myanmar, possibly to Cambodia.
HABITAT
Rivers and lakes of northern Myanmar, including the Ayeyarwaddy River and Lake Indawgyi. Occurs close to the bottom in canals, swamps, ditches, and stagnant waters.
BEHAVIOR
Mostly unknown. This species apparently is sedentary in river or lake beds and moves about slowly.
FEEDING ECOLOGY AND DIET
Feeds mostly on worms and other small, slow-moving benthic invertebrates. Predators are presumably larger fishes.
REPRODUCTIVE BIOLOGY
The reproduction of this species has been observed under captive conditions. Males defended spawning sites of a few centimeters inside a tube and had a lighter reddish brown coloration (instead of the typical darker brown color of nonbreeding males). There is sexual dimorphism in the pelvic fins: males have longer and wider pelvics with inward curving rays. Males displayed by erecting their fins and shaking their tail regions. Females are lighter brown during spawning, with bulging abdomens due to the presence of eggs. Females approached the nesting sites of the male when they were about to spawn (indicated by their protruding genital papillae) and were encouraged to enter the tube by the male. The upside-down female deposited eggs, usually on the roof of the tube; the male fertilized the eggs while also upside-down. Spawning may take several hours, and the male guards the nest. From five to
40 elliptical eggs were laid at a time, measuring about 0.08 in by 0.04 in (2 by 1 mm). Eggs hatched three days after spawning, and larvae were free-living four days after hatching, at about 0.14 in (3.5 mm). Larvae have an attachment organ on the tip of the yolk sac. Larval coloration is unique, composed of three black vertical bands, and adult coloration is attained after more than four weeks and at about 0.3 in (8 mm) in length.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Occasionally imported as an aquarium species.
