Bigfin shrimpgoby

Where they come from

Bigfin shrimpgobies (Vanderhorstia macropteryx) are Indo-Pacific sand flat fish. Think shallow lagoons and rubble zones where there is fine sand, little bits of shell, and tons of small burrows. In the wild they're usually posted up at a shared burrow with a pistol shrimp, peeking out like a periscope and diving back in when something spooks them.

Setting up their tank

If you want this fish to act like itself, give it sand it can actually use. These gobies are miserable on bare bottom and they look stressed when the substrate is too chunky. Mine spent the first day trying to dig under a rock that was sitting on the sand, and that taught me a lesson: rock goes on the glass, sand goes around it.

• Tank size: 20-30 gallons works for a single fish, but bigger is calmer if you have other fish
• Substrate: fine sand (sugar-sized) 2-3 inches deep; a small patch of slightly coarser grains and shell bits is a nice bonus
• Rockwork: stable, resting on the bottom glass or a solid base so burrowing cannot undermine it
• Flow: moderate; you do not want a sandstorm right at the burrow entrance
• Lighting: whatever your reef runs; they do not care much, but they appreciate shaded spots near their burrow

You can keep a Bigfin shrimpgoby alone, but they are at their best with a pistol shrimp roommate. The classic pairings are Alpheus species. If you add the shrimp first and give it a day to start a burrow, the goby usually moves in faster. If you add the goby first, it may pick a random corner and act homeless for a while.

What to feed them

These are little ambush feeders. They sit at the burrow and grab food as it drifts by, so you do not want to rely on them hunting around the tank. New imports can be shy and may not compete well at first, especially if you have fast, pushy fish.

• Frozen: mysis, enriched brine, chopped krill, calanus, finely chopped clam or shrimp
• Live (great for new/shy fish): live brine, small live mysis if you can get it, copepods
• Prepared: small sinking pellets can work once they recognize them, but I still lean on frozen as the staple

I feed small amounts more than once a day if I can. The easiest trick is target-feeding with a turkey baster or pipette, gently puffing food so it lands a few inches up-current of the burrow. Once they learn the routine, they pop out as soon as you walk up.

How they behave and who they get along with

Bigfin shrimpgobies are peaceful and a bit nervous. They spend most of their time hovering at the burrow entrance, doing that classic goby head-bob and quick dart back into the hole. If they feel secure, you will see them out more, and the fin display is really nice.

• Good tankmates: small to medium peaceful fish (clownfish, dartfish, small wrasses that are not bullies, cardinalfish), reef-safe inverts
• Use caution: other sand gobies that want the same real estate, very active diggers that constantly remodel the sandbed
• Avoid: aggressive dottybacks, big hawkfish, predatory wrasses, large triggers, anything that will harass a shy bottom fish

They will stake out a little patch of sand and defend it, but it is mostly bluff and posture. The real problem is them getting outcompeted at feeding time or getting spooked into carpet-surfing. A calmer community makes them a totally different fish.

Breeding tips

In home aquariums, you might see pairing behavior and burrow-sharing (especially if you keep a compatible male/female), but raising the babies is the hard part. Like many marine gobies, the larvae are tiny and planktonic, and they need live foods in the right size range for a while.

• If you think you have a pair, keep the tank steady and do not constantly rearrange the sand and rocks near their burrow
• Feed heavier on small meaty foods to condition them
• If you ever see eggs in the burrow, plan on a separate larval setup with rotifers and later copepods/Artemia - this is not a "leave it in the display" situation

Common problems to watch for

The biggest issues I see with these gobies are not exotic diseases. It is usually simple stuff: stress, starvation, or jumping. If you fix the environment and feeding, they are pretty hardy for a sand-dweller.

• Jumping: almost always from being startled, bullied, or newly introduced without a lid
• Not eating: new fish staying in the burrow and missing food; can snowball fast
• Rock collapses: burrowing under poorly supported rocks can cause a cave-in
• Sandstorms: too much flow or powerheads aimed at the bottom burying the burrow entrance
• Parasites on new arrivals: watch for flashing, rapid breathing, or staying hidden nonstop

If yours is hiding constantly, check two things: is a tankmate pestering it, and is it actually getting food at the burrow? Quiet tank, tight lid, fine sand, and target-feeding near the entrance solves most Bigfin shrimpgoby drama.