🐠 Court Jester Goby (Koumansetta rainfordi)
🐠 Court Jester Goby (Koumansetta rainfordi)
Marine Reef-Safe Nano Goby • Green-Blue Body With Orange Stripes & White Spots • Genuine Algae Grazer • Beginner-Friendly Marine Fish
⚠️ Important Information — Please Read First
We want to be genuinely upfront on this one. This species is genuinely documented to be a finicky feeder, and specimens have been known to decline or even starve without a genuine ongoing supply of filamentous algae and tiny live invertebrate foods in a well-established tank. Please speak with our team about feeding history before purchasing, and be prepared to supplement with algae-rich foods and target feeding if natural grazing isn't sufficient.
📋 The Court Jester Goby, also known as Rainford's Goby or the Old Glory Goby, has a genuinely colourful body in green and blue, with horizontal orange stripes running its length and a row of white spots along the upper back.
Native to a genuinely wide range across the Western Pacific, from the Philippines to the southern Great Barrier Reef and Fiji, this species is genuinely timid and peaceful, and does best in a well-established tank with plenty of live rock and sand to graze.
It's fully reef safe, and genuinely a valuable grazer, documented eating hair algae and even red cyanobacteria. We want to be honest that it's best kept singly, or as a known pair in a genuinely large tank with abundant hiding places. It's also a genuine expert jumper, so a tight-fitting lid is essential.
🟢🟠 Highlights
🎨 Green-Blue Body With Orange Stripes: A genuinely colourful, popular nano goby
🌿 Fully Reef Safe: Won't harm corals or invertebrates
🪴 Genuine Algae Grazer: Documented eating hair algae and cyanobacteria
⚠️ Genuinely Can Be a Finicky Feeder: Needs an established tank with real natural grazing
⚠️ Genuine Expert Jumper: A tight-fitting lid is essential
🧾 A Quick Look at the Court Jester Goby
📛 Common Name: Court Jester Goby (Rainford's Goby, Old Glory Goby)
🔬 Scientific Name: Koumansetta rainfordi
👨👩👧 Family: Gobiidae
🌍 Origin: Western Pacific (Philippines to southern Great Barrier Reef, Fiji)
📏 Max Size: Up to 8.5 cm (≈ 3.3")
🧂 Specific Gravity: 1.020–1.025
🌡️ Temperature Range: 22–26°C (72–78°F)
🧠 Care Level: Moderate — genuine feeding difficulty possible
💖 Temperament: Peaceful; genuinely timid
🌿 Reef Safe: ✅ Yes
🏠 Min Tank Size: 40 L (≈ 10 gallons)
📌 Tank Level: Bottom / Sand Bed
🧬 Stock Type: Wild-collected as standard stock; genuinely also captive-bred by some suppliers
⏳ Lifespan: 3–5 years
🍽️ Diet: Omnivore (filamentous algae, cyanobacteria, small invertebrates)
🐣 Reproduction: Egg Layer; genuinely can spawn in home aquariums, though larvae are extremely difficult to raise

















