Flaming Arrow Goby (Sicyopus zosterophorus)

Common Name

Flaming Arrow Goby

Origin and Habitat

Sicyopus zosterophorus is found in island streams across parts of Southeast Asia and the Western Pacific. It lives in clear, fast flowing freshwater that tumbles down from forested hills. The water is highly oxygenated, the flow is strong, and the bottom is rocky with boulders, cobble, and coarse gravel. These gobies cling to hard surfaces with a pelvic suction disc and graze or hunt across sunlit stones where algae, biofilm, and tiny invertebrates thrive.

Temperature and Water Conditions

Preferred temperature is 22 to 26 °C, which is about 72 to 79 °F. In the wild they are often recorded from neutral to slightly alkaline water, about pH 6.8 to 7.5, with hardness that varies by watershed. We do not recommend chasing or altering water parameters except in special breeding situations. Stable, clean, well oxygenated water is far more important than any exact number.

Appearance and Size

Adults show a vivid flame streak on the tail and rear body that gives the species its common name. The body is slender and built for current, with a strong head and a fused pelvic fin that forms a suction cup. Males usually carry richer color and sharper markings, especially during courtship. Females are a bit subtler. Maximum length is about 6 cm, which is about 2.4 inches.

Diet in the Wild

These stream gobies pick at the substrate and take small prey moving in the current. The natural menu is a mix of micro invertebrates, insect larvae, tiny crustaceans, and the biofilm community that coats rocks. They use quick darts and short sprints, then rest and hold position on stone.

Feeding in Captivity

Offer small, frequent foods that match their natural bite size. Good choices include live or frozen baby brine shrimp, cyclops, daphnia, finely chopped blackworms, and high quality micro pellets that sink. Encourage natural grazing by placing smooth river stones under bright light so algae and biofilm can develop. A mature tank with established biofilm helps new arrivals settle and feed confidently.

Behavior and Tank Setup

This is a lively current lover that perches, dashes, and explores. Temperament is generally peaceful, with males showing mild territorial displays toward other males. Provide sight breaks and plenty of rock faces so everyone can claim a patch. A river style aquascape works best, with rounded stones, coarse sand or fine gravel, and strong aeration. Use powerheads or a river manifold to create directional flow, and keep the water in the cool to mid seventies with a tight lid. A group of three to six in a twenty to thirty gallon river tank or larger works well. Tank mates should enjoy similar conditions. Hillstream loaches, small danios, ricefish, and other peaceful stream fish are great choices. Avoid large or pushy species. Cover filter intakes since these are enthusiastic explorers.

Breeding

Sicyopus and its relatives follow an amphidromous life cycle. Adults spawn in freshwater, usually on hard surfaces where the male guards adhesive eggs in cavities or under stones. After hatching, larvae drift downstream and develop in brackish to marine plankton before returning to freshwater as tiny juveniles. In home aquaria, courtship and egg laying can occur if you provide caves and rock piles with gaps. A stack of flat rocks and larger gravel helps eggs fall out of easy reach and stay protected. Raising the larvae past the first days requires specialized rearing in saline water with very fine plankton foods, which is an advanced project.

Quick Facts

• Scientific name: Sicyopus zosterophorus
• Origin: Island streams in Southeast Asia and the Western Pacific
• Size: Up to 6 cm, about 2.4 in
• Temperature: 22 to 26 °C, 72 to 79 °F
• pH: About 6.8 to 7.5 in the wild
• Temperament: Peaceful, males may spar lightly
• Diet: Micro invertebrates and biofilm in the wild, small frozen and live foods in captivity
• Tank style: High oxygen, strong flow, rocks and coarse substrate
• Breeding: Amphidromous, eggs in freshwater, larvae require marine rearing