Barred mudskipper

1) Where they come from

Barred mudskippers (Periophthalmus argentilineatus) are little amphibious gobies from mangroves, tidal flats, and muddy shorelines across the Indo-Pacific. They spend a ridiculous amount of time out of the water, hopping around, squabbling over territory, and darting back in when they feel like it.

If you’ve ever watched one in a shop and thought “that’s a fish with lizard energy,” you’re not wrong.

2) Setting up their tank

This species is the reason I tell people: you’re not setting up an aquarium… you’re building a shoreline. A mudskipper tank lives or dies by having a big land area, warm brackish water, and a lid that they can’t defeat.

Tank size depends on how many you want and how much land you can give them. For a single barred mudskipper, I’d start around a 20 long-style footprint. For a small group, bigger is better because floor space and shoreline matter more than gallons.

• Big footprint tank (long/wide beats tall every time)
• Land area: sand/mud slope or raised platform so they can haul out easily
• Brackish water: aim roughly 1.005–1.012 specific gravity (most do well mid-range); use marine salt mix, not “aquarium salt”
• Temp: warm (mid-to-high 20s °C / upper 70s to low 80s °F)
• Filtration: solid biofilter + gentle flow (they don’t need a river blasting their shoreline)
• Heater guard: they will perch on weird stuff
• Lighting: enough for you to see them and for any hardy brackish plants/algae, but don’t cook the land area

For substrate, I’ve had the best luck with a sand-heavy mix. Super fine mud looks cool but turns into a nasty anaerobic mess if you don’t manage it. You can still get that muddy aesthetic by letting biofilm and algae build up on rocks and wood near the waterline.

Decor-wise, give them sight breaks and perches: smooth rocks, mangrove-style roots, sturdy driftwood (soaked well), and a couple “high points” they can claim. They like having a lookout spot.

3) What to feed them

They’re enthusiastic predators, and feeding time is half the fun because they’ll stalk, pounce, and sometimes steal from each other like tiny swamp goblins.

• Staples: frozen/thawed bloodworms, mysis, chopped prawn/shrimp, chopped clam/mussel
• Treats: live blackworms (if you can source clean ones), small crickets or roaches (careful—don’t overdo insects), live ghost shrimp in the water
• If you can get them onto pellets: sinking carnivore pellets can work, but many prefer meaty foods

I usually feed smaller amounts more often rather than one giant meal. They’ll beg and they’ll act starving… they’re lying. Watch body shape: you want them nicely filled out, not bloated.

4) Behavior and tankmates

They’re bold, territorial, and way more interactive than most fish. Expect posturing, fin-flaring, pushing matches, and lots of “this is my rock” drama. Some squabbling is normal; relentless bullying is not.

Tankmates are tricky because mudskippers want land, and most brackish fish want water… plus mudskippers will try to eat anything that looks snack-sized. I’ve had the best results either species-only, or with carefully chosen brackish fish that stay in the water column and are too big to be eaten.

• Best option: species-only, especially if you’re new to them
• Possible tankmates (with a big tank and lots of structure): larger mollies, some monos/scats when young (but they outgrow many setups), bumblebee gobies sometimes—but only if the mudskippers aren’t food-motivated and the tank is roomy
• Avoid: small shrimp/crabs you care about, tiny fish, slow long-finned fish, anything that needs pure freshwater or full marine

5) Breeding tips (the honest version)

They can be bred, but it’s not a casual “oops babies” fish. Males dig burrows in the substrate and guard them, and success is tied to having deep, diggable material, stable brackish conditions, and a lot of space for territories.

• Give them depth where it counts: a section with several inches of sand/mud mix so burrows can hold shape
• Keep the tank quiet and stable—constant rescapes and big disturbances seem to shut down digging behavior
• Condition them with heavy meaty feeding and warm temps
• Expect aggression to ramp up around nesting behavior

6) Common problems to watch for

Most mudskipper issues trace back to one of three things: not enough land, wrong salinity (or swinging salinity), and injuries from fighting or escapes.

• Escapes/desiccation: they launch themselves and can dry out fast
• Skin damage: rough decor, sharp rocks, or ammonia/nitrite problems show up as sores and frayed fins
• Bullying: one fish pinned in the water and not allowed onto land is a big red flag
• Salinity creep: topping off with saltwater instead of fresh slowly ramps SG up
• “New tank funk”: they don’t appreciate immature filtration—brackish tanks still cycle like any other
• Refusing food: often stress from lack of hides/land, incorrect temps, or being outcompeted

If you get the shoreline layout right and keep the brackish side stable, these guys are unbelievably rewarding. They recognize you, they have personalities, and they make even a small tank feel like a living little ecosystem.