Spikefin goby

Where they come from

Spikefin gobies (Discordipinna griessingeri) are tiny, flashy little sand-gobies from the Indo-Pacific. You usually find them in shallow lagoons and reef flats where there's fine sand, scattered rubble, and small holes to duck into. In the tank they act the same way: hang low, perch, hop, and vanish the second they feel exposed.

Setting up their tank

Think small fish, big need for "micro habitat." You can keep one in a nano, but it has to be mature and stable, with real hiding spots and gentle flow along the bottom. These guys do best once your tank has some life in it - pods, worms, film algae, the normal reef "grime" that builds up over time.

• Tank size: 10+ gallons can work for a single fish, 20+ is more comfortable and forgiving
• Substrate: fine sand is your friend (they perch and scoot along it)
• Rockwork: lots of little caves and overhangs, plus a few rubble piles
• Flow: moderate overall, but give them calmer zones at the bottom
• Lighting: whatever your reef runs - they do not need special lighting, they need cover

I also like to add a few small bits of shell, coral rubble, or little "chambers" between rocks where they can claim a spot. They are bold once they have a home base, but they sulk and hide if the tank is too open.

What to feed them

Feeding is the main reason I call them intermediate. Some individuals eat frozen right away, some act like frozen food is invisible. The ones that struggle usually do not starve overnight, but they can slowly fade if you do not get consistent food into them.

• Best starters: live baby brine shrimp (enriched if you can), live copepods, live blackworms (if you have a safe saltwater source/setup)
• Frozen they often accept: mysis (small), calanus, finely chopped brine, roe, small "reef plankton" blends
• Prepared foods: sometimes tiny pellets, but I would not rely on them at first

New spikefins do better with multiple small feedings. Early on I aim for 2-3 light feedings a day, then back off once I see a nice rounded belly and regular hunting behavior. If your tank is full of aggressive eaters, you will be fighting an uphill battle.

How they behave and who they get along with

They are peaceful, a little shy, and very "bottom focused." Most of the time you will see them perched like a tiny hawk, then doing quick little hops between spots. They are not a sand-sifter and they do not bulldoze the scape, which is nice.

• Good tankmates: small, calm fish (firefish, small assessors, tiny cardinals), gentle gobies, small blennies that are not pushy, reef-safe inverts
• Use caution with: dottybacks, bigger wrasses, hawkfish, bigger clowns, damsels, or anything that "owns" the bottom
• Avoid: predators and fast, competitive feeders that keep them pinned in hiding

Conspecific aggression can happen in small tanks. A bonded pair can work, but two random spikefins in a tight space is a coin flip. If you try a pair, give them lots of structure and watch closely at feeding time.

Breeding tips

They can spawn in captivity, usually in a little cave or under rubble. The hard part is raising the larvae, not getting them to lay eggs. If you ever see the pair hovering around a specific nook and the male posting up at the entrance, you might be close.

• Give them choices: several small caves and tight crevices near the sand
• Feed heavier (but not sloppy) to condition them: small meaty foods, frequent small meals
• If you want to raise babies: you will need a larval setup and tiny live foods (rotifers and appropriate phyto/copepod cultures)

Common problems to watch for

The big three with spikefins are starvation, jumping, and stress from tankmates. If you solve those, they are actually pretty hardy for such a small fish.

• Not eating: try live foods for a week, reduce competition, and feed right at their perch
• Getting outcompeted: move them to a quieter tank or use a feeding dome/target feeding
• Jumping: lid/mesh top, block tiny gaps around cables and plumbing
• Hiding nonstop: too much light and not enough cover, or a bully in the tank
• Skin/fin issues (marine ich/velvet): quarantine if you can, and do not add them to a "hot" tank with recent disease history

If you are picking one out at the store, watch it eat if possible. I have had way better luck starting with a fish that already recognizes frozen or at least shows strong hunting behavior in the holding tank. It saves you weeks of stress.