Cebu Orange Tail Goby (Sicyopus Cebuensis)

In Cebu’s swift streams, a small goby signals with a flame-orange tail.

Meet the Cebu Orange Tail Goby (Sicyopus cebuensis): a striking, current-loving freshwater goby for mature, well-oxygenated riffle aquariums with strong flow.

• Water conditions: Sicyopus cebuensis is a rheophilic freshwater goby, so replicate a clean, fast-flowing stream rather than a calm community tank. Aim for 22–26°C, pH 6.5–7.8, GH 4–12 dGH and KH 2–6, with 0 ppm ammonia and nitrite and nitrate kept below 20 ppm. Provide high turnover — roughly 8–12 times the tank volume per hour — using powerheads or wavemakers aimed along the rockwork, plus strong surface agitation for high dissolved oxygen. Avoid stagnant corners, heavy organic waste and sudden temperature swings. Adults are freshwater fish, but the species is amphidromous: breeding involves a brackish/marine larval phase and is not expected in a standard aquarium. Drip-acclimatise new arrivals slowly and never rush them into a newly set-up tank.
• Tank setup and size: A 90 cm / 100-litre-plus riffle-style aquarium is a sensible minimum for a stable, high-flow setup. Use smooth rounded cobbles, pebbles, driftwood, caves and a fine sand or gravel substrate; avoid sharp or rough decor that can damage the goby’s skin and fins. Build low-current resting pockets behind rocks while keeping the main flow strong. A mature tank with visible biofilm and algae on stones is ideal. Use a tight-fitting lid, as these gobies can jump, and ensure filter intakes are guarded so small fish cannot be drawn in.
• Suitable tank mates: Best kept in a species-focused riffle tank or with peaceful, current-loving fish of similar size, such as small danios, Microdevario, Devario, Garra, Stiphodon and Rhinogobius species. Robust shrimp may work in a well-structured setup, but tiny shrimp and fry can be eaten. Avoid slow-moving, long-finned, predatory or boisterous tank mates, as well as fish that need warm, still water. These gobies can be territorial, especially males toward other males, so keep one male per tank or use a large, rock-rich aquarium with broken sightlines and multiple females. Do not house with aggressive cichlids, goldfish or other messy, high-waste species.
• Feeding habits: The Cebu Orange Tail Goby is an omnivorous grazer and aufwuchs feeder. In a mature aquarium it will browse biofilm and algae from rocks and glass, but do not rely on tank algae alone. Offer spirulina or algae wafers, sinking pellets, Repashy-type gels, blanched zucchini, cucumber and spinach, plus small amounts of frozen baby brine shrimp, daphnia, cyclops and bloodworm. Many specimens ignore dry food at first, so start with frozen and gel foods and gradually train them onto sinking pellets. Feed two to three small portions daily and remove uneaten food to protect water quality. Watch for weight loss or sunken bellies, which can indicate insufficient biofilm or competition.
• Care requirements: This is not a beginner fish. It needs a mature, stable, highly oxygenated aquarium with excellent filtration, regular partial water changes of around 20–30% weekly, and gentle substrate cleaning. Keep the water cool-to-temperate within the stated range, avoid overstocking and maintain strong flow without creating relentless turbulence in every corner. Quarantine new arrivals and acclimatise by drip method. Handle medications and copper-based treatments with caution, and avoid exposing the goby to sudden changes in temperature, pH or oxygen levels. Because the species is amphidromous and captive breeding is rare, most available specimens are wild-caught; choose a responsible supplier and inspect fish for clear eyes, active grazing behaviour and intact fins before purchase.
• Behaviour and adult size: Adult Sicyopus cebuensis are small gobies, typically reaching around 4–5 cm, with males showing the attractive orange caudal fin that gives the species its common name. They are active, bottom-oriented fish that spend much of their time clinging to rocks and grazing in current. Provide plenty of visual barriers and smooth surfaces. They may become territorial with their own kind, so observe group dynamics carefully. A quiet, mature riffle aquarium with stable parameters, strong flow and abundant biofilm gives this species the best chance of long-term health and natural behaviour.