Eastern longfin goby
Favonigobius lentiginosus
The Eastern longfin goby features a slender body with a mottled brown and cream coloration, distinguished by long pectoral fins and a fused dorsal fin.
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About the Eastern longfin goby
This is a little sand-loving coastal goby that hangs around estuaries, mangroves, tidepools, and sandy flats, and it does that classic goby thing of perching and scooting along the bottom. Color-wise its pretty subtle but really neat up close - sandy brown with distinct bars and head striping - and it spends a lot of time hunting tiny crustaceans in the substrate.
Also known as
Quick Facts
Size
6 cm
Temperament
Peaceful
Difficulty
Advanced
Min Tank Size
20 gallons
Lifespan
2-4 years
Origin
Australia and New Zealand
Diet
Carnivore/micro-predator - small crustaceans (copepods, amphipods), worms; frozen mysis/brine and other meaty micro foods
Water Parameters
18-26°C
7.8-8.4
8-20 dGH
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Calculate heater sizeCare Notes
- Give it a big, open sand flat with some rubble and a couple low rock overhangs - they want room to hop and perch, not a packed reef wall.
- They hate swings: keep salinity steady around 1.024-1.026 and temp about 22-26 C (72-79 F); sudden top-off mistakes are a fast way to stress them out.
- Fine sand is non-negotiable - coarse crushed coral can tear up their fins and belly when they scoot and bury.
- Feed like a predator: small meaty stuff (mysis, chopped prawn, enriched brine, copepods) and target feed near the bottom so faster fish do not steal it all.
- Skip boisterous tankmates (dottybacks, aggressive wrasses, big hawkfish) - they get outcompeted and may get fin-nipped; calm sand-friendly fish and non-predatory inverts work best.
- Lock the lid down tight - longfin gobies launch when spooked, and they can clear tiny gaps around plumbing and cables.
- Watch for 'mysterious' decline that is really starvation or bullying - if it is hiding all day or losing weight, move it to a quieter tank and feed heavier.
- Breeding is possible if you give tight caves or short PVC pieces; the male tends the eggs, and the larvae go planktonic, so raising babies is a whole separate live-food project.
Compatibility
Good Tankmates
- Small, chill sand-sitters like watchman gobies or small shrimp gobies (as long as youve got lots of bottom space and a few little caves so nobody has to argue over the same patch of sand)
- Peaceful nano-to-small reef fish that keep to themselves, like firefish and dartfish - theyre mellow and wont hassle a shy goby
- Calm midwater fish like ocellaris/percula clownfish (a settled pair is usually fine) - they mostly do their own thing up in the water column
- Small peaceful wrasses that arent bullies, like a possum wrasse - they cruise for pods and leave bottom gobies alone
- Cardinalfish (like banggai cardinals) - slow, non-nippy, and theyre not competing for the same real estate on the sand
- Gentle cleanup buddies like small nassarius snails and sand-sifting inverts (the goby will ignore them, and they wont outcompete it for food if you target feed a bit)
Avoid
- Triggerfish and big hawkfish - anything that thinks a small bottom fish looks like a snack or a chew toy
- Aggressive dottybacks (like pseudochromis) - they love to claim caves and will run a peaceful goby ragged
- Big territorial damsels - the kind that patrol the whole tank and pick on anything that blinks
- Puffers and large, nosy wrasses that peck and pester - constant attention stresses these guys out and theyll stop coming out to eat
Where they come from
Eastern longfin gobies (Favonigobius lentiginosus) are little sand gobies from southern and eastern Australia. You find them in bays, estuaries, and sheltered coastal flats where the bottom is soft sand or fine rubble. They spend a lot of time parked on the substrate, watching the world go by, then doing quick little hops to grab food or change perches.
A lot of the ones that show up in the hobby have lived in swingy estuary conditions. That does not mean they like sloppy water, but it does mean they can be sensitive to sudden changes from shipping and acclimation.
Setting up their tank
Think "open sand with hiding spots". If you set them up like a rock-perching reef fish, they just look stressed and you will barely see them. Give them a decent sand bed and some low caves or overhangs so they can tuck in without having to wedge into sharp rock.
- Tank size: I would not do one in less than 20-30 gallons, and bigger is nicer if you want tankmates.
- Substrate: fine sand is your friend. Coarse crushed coral can scrape them up and they do a lot of belly contact.
- Rockwork: keep it stable and on the glass or on supports, not sitting on top of deep sand they might dig around.
- Flow: moderate, but do not blast the sand flat. Give them calmer "parking" areas.
- Filtration: strong biofiltration and a skimmer help because you will be feeding heavier than you expect for a small fish.
- Lid: they can hop, especially when spooked. A tight lid saves you heartache.
Acclimate slow and dim the lights the first day. I have had gobies that acted "fine" in the bag and then went downhill fast if the first few hours were too rough.
For parameters, keep it reef-like and steady. Salinity around 1.024-1.026, stable temperature in the mid-70s F (24-26 C), and low ammonia and nitrite always. Nitrate is less scary than swings, but you will get better feeding response and fewer skin issues when nitrate stays reasonable.
What to feed them
This is where the "advanced" label really fits. Many longfin-type gobies come in skinny and they do not always recognize pellets right away. They are micro-predators that want small meaty stuff drifting or bouncing along the bottom.
- Best starters: live or frozen mysis (small), enriched brine shrimp, chopped krill, finely chopped clam or prawn.
- Small foods they really pick at: copepods, amphipods, Calanus, roe, and other tiny frozen blends.
- Once settled: some will take sinking pellets, but I treat that as a bonus, not the plan.
Target feeding works. Use a pipette or turkey baster and drop food right in front of their perch so it puffs onto the sand. They learn fast, and you waste way less food.
Feed small amounts more often at the start. A new fish that is thin does better with 2-3 small feedings than one big dump. If you have a pod population in the tank or refugium, that helps a lot during the "not sure what food is" phase.
How they behave and who they get along with
They are bottom-focused, a bit shy, and usually not aggressive in the classic "reef fish" way. The main drama is food competition and being bullied off their spot. If they cannot relax on the sand and watch for snacks, they slowly fade.
- Good tankmates: calm fish that do not live on the sand - small wrasses that are not hyper, peaceful cardinals, small anthias in larger tanks, mellow blennies that stick to rock.
- Risky tankmates: fast, greedy feeders (many damsels), dottybacks, larger wrasses, and anything that treats the sand as its personal racetrack.
- Do not mix with: predatory fish that see a goby as a snack, and heavy sand-sifters that constantly dump sand on them.
Watch out for other bottom dwellers. Even "peaceful" fish can make a goby miserable just by outcompeting it every single meal.
They may dig little divots or use existing caves, but do not expect the classic shrimp-goby partnership. Some individuals will sit near burrowers and take advantage of the extra food movement, but I would not buy one hoping for a bonded pair behavior.
Breeding tips
Breeding in home aquariums is possible in the general goby sense (cave spawning, male guarding eggs), but raising the larvae is the real wall. If you manage to get a bonded pair, they will usually pick a snug cave or a little tunnel under rock and lay eggs on the roof or wall.
- Give them options: small rock caves, short lengths of PVC tucked under rock, and stable sand around the entrance.
- Conditioning: lots of small meaty foods and stable water. A well-fed female looks noticeably fuller behind the head and along the belly.
- If they spawn: the male often stays close and fans the clutch. Keep tankmates calm so he does not abandon it.
Larvae are planktonic and tiny. If you are serious, you are looking at a separate larval setup, live rotifers, and a plan for greenwater and copepods. Most hobbyists stop at "cool, they spawned" and that is totally fine.
Common problems to watch for
Most issues I have seen come down to stress plus not eating enough. These fish can look "okay" for a week and then suddenly crash because they never really started feeding.
- Refusing food: usually shipping stress or too much competition. Try smaller foods, target feed, and reduce bright lighting for a bit.
- Getting pinched in the belly: not enough calories, or food is too big. Switch to smaller meaty items and feed more often.
- Abrasion or red patches on the belly: rough substrate or unstable rockwork shifting. Fine sand and stable structures fix a lot.
- White spot/velvet: they can be sensitive. Quarantine if you can, and do not rush treatment without confirming what you are seeing.
- Jumping: spooked fish + no lid = loss. This is one of the easiest problems to prevent.
If you see rapid breathing, hanging in the flow, and a dusty or "matte" look to the skin, treat it like an emergency. Do not wait a week hoping it clears on its own.
If you keep the sand comfortable, keep tankmates from stealing every meal, and make feeding easy for them at the start, they are rewarding little fish. You end up with a neat bottom sentry that is always watching you back.
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