Long-finned goby

Where they come from

Long-finned gobies (Valenciennea longipinnis) are Indo-Pacific sand sifters. You find them on shallow sandy flats and rubble zones from Japan down through Indonesia and into Australia. They pair up, dig little burrows under rocks, and spend the day gulping sand and spitting out clean grains like tiny excavators.

Setting up their tank

Give them space to patrol the sand and a safe place to dig. A single does fine in a 30-40 gallon tank, but they appreciate more floor space. If you want a pair, think 50+ gallons.

• Lid: tight-fitting cover with every gap sealed. They jump.
• Substrate: 2-3 inches of fine sand (0.5-1.5 mm). Skip coarse crushed coral.
• Rockwork: set rocks directly on the glass or eggcrate before adding sand so burrows do not cause rock slides.
• Flow: moderate, with calmer zones along the bottom so food settles.
• Mature system: they do best in tanks with a lived-in sand bed full of pods and worms (6+ months old is great).
• Lighting: not fussy; aim your light and flow so sand does not blow onto delicate corals.

What to feed them

In the wild they eat tiny crustaceans and worms in the sand. In our tanks they still sift all day, but that alone rarely keeps them full, especially in newer systems. Plan on feeding small, meaty foods that sink.

• Frozen mysis (chopped if large)
• Calanus, cyclops, or other small plankton
• Enriched brine shrimp (as a treat, not the main food)
• Finely chopped clam, shrimp, or fish
• High-quality small sinking pellets (soaked first so they drop fast)

New arrivals can be picky. Target-feed near their burrow at first so the food hits the sand right in front of them. I like to turn off the return for 5-10 minutes so it all stays in the display. Two smaller feedings a day beats one big one while they put weight back on.

How they behave and who they get along with

They are peaceful, busy workers that mind their own business. Expect a lot of sifting, short dashes between burrow and feeding spots, and some redecorating. They may carry mouthfuls of sand up onto rock ledges and spit it out, which can dust nearby corals.

• Good tankmates: peaceful community fish (chromis, fairy wrasses, smaller tangs), most gobies that are not sand sifters, clownfish, dartfish.
• Use caution: other Valenciennea or sand-sifting species. They compete and may fight unless you have a confirmed pair.
• Avoid: bullies like large wrasses that harass bottom dwellers, aggressive dottybacks, and very territorial damsels.

Breeding tips

They form pairs and spawn in a burrow or cave, gluing eggs to the roof. You can sometimes buy a bonded pair; sexing singles is tough. In a calm tank with steady food, a pair may set up house and spawn without fanfare.

• Give them a stable cave under a rock or a short piece of PVC partly buried in sand.
• Keep the area quiet and avoid constant rescapes once they choose a spot.
• Feed well with varied, meaty foods to condition them.

Common problems to watch for

• Jumping: the number one cause of loss. Cover every gap around pipes, cords, and the overflow.
• Starvation in new tanks: a thin, pinched-in belly means it needs more frequent, meaty feeds.
• Mouth abrasions: shows up as a raw or whiteened mouth from sifting coarse substrate.
• Burrow cave-ins: unsecured rock can shift. Set rock on the glass, not on sand.
• Sandstorms and buried frags: they move sand. Elevate small corals or secure them well.
• New fish stress: they hide at first. Keep lighting a bit dimmer the first few days and feed calmly near their burrow.
• Parasites: like other marine fish, they can carry ich. Quarantine if you can.