Midnight Goby (Lentipes Dimetrodon)

A shadow-dark stream goby with a sail-like dorsal fin, haunting freshwater currents.

Meet the Midnight Goby (Lentipes dimetrodon), a striking freshwater stream goby with a sail-like dorsal fin. Buy healthy specimens from our premium aquatics store.

• Water conditions: The Midnight Goby is a rheophilic species from fast-flowing tropical streams and demands cool, highly oxygenated, pristine water. Aim for a temperature of 20–24°C (68–75°F) and avoid prolonged exposure above 26°C, which stresses the fish and suppresses its immune system. pH should sit between 6.5 and 7.5, general hardness around 4–10 dGH, and carbonate hardness around 2–6 dKH. Ammonia and nitrite must remain at zero, and nitrate should be kept below 20 ppm, ideally below 10 ppm. Provide strong, turbulent current with a turnover of 10–20 times the tank volume per hour using a river manifold, powerheads, or a large canister filter with spray bars. Dissolved oxygen must be high, so position powerheads to agitate the surface. Use smooth rounded stones, coarse sand or fine gravel, and biofilm-rich cobbles. Perform 25–30% weekly water changes with temperature-matched, dechlorinated water, and avoid large parameter swings. This species is sensitive to dissolved organics and declining water quality, so overfiltration and excellent aeration are essential.
• Suitable tank mates: Choose peaceful, current-loving fish that thrive in cool, oxygen-rich water and will not bully or outcompete the goby. Excellent companions include white cloud mountain minnows, small danios, slender rasboras, and hillstream loaches such as Sewellia and Pseudogastromyzon species. Small, non-aggressive gobies of similar size may work in a spacious river-style setup with ample grazing surfaces. Avoid large or boisterous cichlids, goldfish, slow-moving bettas, and aggressive loaches that may dominate feeding stations or harass the goby. Avoid mixing with species that prefer warm, still water, because the required temperature and flow compromise their health. Adult ornamental shrimp are usually safe, but very small shrimp and shrimplets may be predated, so treat them as a potential snack. Ensure the tank has enough biofilm-covered rockwork to support multiple grazers, and observe feeding closely during the first weeks. Quarantine all new arrivals before adding them to the display to reduce the risk of introducing disease.
• Feeding habits: The Midnight Goby is an omnivorous grazer that naturally feeds on aufwuchs — a mixture of algae, biofilm, microfauna, and detritus — from rocks and submerged surfaces. In the aquarium, provide a mature tank with visible biofilm on smooth stones and driftwood. Supplement grazing with spirulina wafers, algae-based sinking pellets, and small amounts of live or frozen foods such as daphnia, bloodworm, brine shrimp, cyclops, and microworms. Feed two to three small portions daily rather than one large meal, ensuring food reaches the bottom where the goby forages. Because the strong current disperses food quickly, target-feed near calm eddies behind rocks or use a pipette to deliver frozen foods directly to grazing areas. Avoid overfeeding, as uneaten food fouls the water and raises nitrate. Monitor body condition: a healthy goby shows a rounded belly and active grazing behaviour. If the fish appears thin, increase the frequency of small meaty feeds while maintaining excellent water quality. Never rely on algae alone in a newly set-up aquarium.
• Care requirements: Acclimatise the Midnight Goby carefully using the drip method over 45–60 minutes, matching temperature and water chemistry to reduce stress. Quarantine new specimens for two to four weeks and observe for signs of disease, weight loss, or injury. This species is an accomplished jumper, so a tight-fitting lid with no gaps is essential. Provide a river-style aquascape with smooth cobbles, driftwood, and robust plants such as Anubias and Java fern attached to rockwork; avoid sharp edges that can damage the goby’s skin and fins. Maintain strong flow, cool temperatures, and high oxygen levels year-round. Test water parameters weekly and keep a consistent maintenance schedule; this fish is sensitive to ammonia, nitrite, and sudden changes. Avoid unnecessary copper-based medications, as gobies can be sensitive to copper. Breeding is unlikely in the home aquarium because the species is amphidromous and its larvae require a brackish or marine phase. Handle only when necessary, using a container rather than a net, and never expose the fish to air longer than required. With stable water, mature biofilm, and correct flow, the Midnight Goby can be a fascinating and long-lived centrepiece for the advanced river-tank aquarist.