Rao's hover goby

Where they come from

Rao's hover goby is a tiny coastal fish from the Indo-Pacific, often found nosing around mangrove edges, sandy shallows, and seagrass beds. They hang just off the bottom and dart into little cracks and shell piles the second something spooks them.

Setting up their tank

They are small, but give them room to feel safe. A mature 10-20 gallon tank works for a pair. These guys appreciate a calm, pod-rich setup more than flashy gear. Think gentle flow, lots of micro-habitats, and a tight lid.

• Substrate: fine sand with some crushed coral or shell bits they can duck under
• Hardscape: porous live rock, small caves (bits of PVC, snail shells, rubble piles)
• Flow: low to moderate with calmer zones near the bottom
• Lighting: moderate; they are not seekers of bright spotlight
• Cover: tight-fitting lid or mesh (they jump)
• Mature biology: let the tank run a while so copepods/amphipods are established

I like building a couple of rubble mounds with pea-sized rock and shells. They will park just above these and retreat inside whenever a bigger fish cruises by. If you can run a small refugium or even just seed pods regularly, life gets easier.

What to feed them

They have pin-sized mouths and hunt tiny zooplankton. New arrivals often ignore flakes and big frozen foods, so start small and lively, then transition.

• Live foods to start: copepods, enriched newly hatched brine shrimp, live baby mysis (if you can get it)
• Frozen micro foods: cyclops, calanus, fish eggs, finely shaved mysis, lobster eggs, reef plankton
• Dry options: high-quality micro pellets can work once they recognize non-moving food

Feed small amounts 2-3 times a day. Target feeding with a pipette helps a ton. I switch off the flow for a few minutes, squirt a small cloud just above their hangout, and watch to make sure food is actually going in, not just floating past.

How they behave and who they get along with

They hover a few inches above the substrate, pick at drifting specks, and perform quick dashes to cover. Shy at first, but once settled they keep a steady patrol. You can keep a single, a pair, or a small group if the tank has sight breaks.

• Peaceful neighbors: tiny gobies (neon, clown), small cardinalfish, pipefish and seahorses in species/nano setups, tailspot blennies, cleaner shrimp, snails
• Sketchy choices: mandarins and pipefish compete for the same pods in small tanks
• Avoid: hawkfish, dottybacks, larger wrasses, aggressive basslets, anything that sees them as a snack

Breeding tips

They are cave spawners. A bonded pair will pick a small cavity, lay adhesive eggs, and the male usually does the guarding and fanning. You might notice the pair lingering in one hide and fending off nosy neighbors.

• Set up multiple tiny caves: sections of airline tubing, 1/2 inch PVC, empty snail shells
• Feed heavy on small live and frozen foods to get them in condition
• Leave them undisturbed; the male will guard until hatch
• Larvae are planktonic and very small. Plan on a separate rearing container with gentle air, greenwater, and rotifers/copepod nauplii from day 1
• Transition larvae to enriched baby brine as they grow, then to larger micro foods

Common problems to watch for

• Starvation: they can slowly waste away if they never accept prepared foods. Watch the belly line and adjust feeding.
• Shipping and acclimation stress: drip acclimate gently and give them quiet time with the lights low.
• Jumping: any sudden movement can send them airborne. Use a lid.
• Bullying: even a semi-pushy fish can keep them pinned in a corner, which kills appetite.
• Parasites: tiny gobies often arrive thin. Quarantine and consider medicated food if you see white stringy feces or persistent weight loss.
• Salinity swings: they are small; big swings hit hard. Keep top-off regular and changes measured.