Sixspot goby (Valenciennea sexguttata)

Choose it for a mature marine aquarium

The Sixspot goby (Valenciennea sexguttata) is a marine goby in the family Gobiidae. It comes from the Indo-Pacific, where its range extends from the Red Sea, Persian Gulf and East Africa to Samoa, north to the Yaeyama Islands and south to Queensland. FishBase records a maximum length of 14 cm. This fish suits a keeper who can provide a mature, filtered marine aquarium, plan around a bottom-associated fish and maintain a consistent feeding and water-care routine.

Keep the aquarium at 24–26°C. That routine range is the overlap between FishBase’s recorded wild environment of 22–28°C and OATA’s goby guidance. OATA also recommends salinity of 1.020–1.025, pH 7.9–8.3 and carbonate hardness of 8–12°dKH for gobies as a group; these are not a species-specific optimum.

At 14 cm, this fish belongs in OATA’s larger-goby planning category. Use an aquarium of at least 120 litres for one, and plan a larger aquarium when it will live with other fish. The volume is a starting point for stability and stocking decisions rather than permission to add any particular companion.

Understand the animal in this offer

One purchase supplies one Sixspot goby. The 14 cm figure is its recorded adult planning length, not a statement of the fish’s length at dispatch. Build the permanent aquarium around that adult size from the outset rather than using a smaller temporary volume.

Sex is guaranteed only when the selected option explicitly states male or female. This Sixspot goby listing has no sex-guaranteed option. Do not use colour, apparent size or the gallery image to decide whether the fish will be male or female.

The gallery images are representative of this type of animal rather than photographs of the exact animal supplied, so colours can look slightly different from the live animal. Use the gallery to recognise the overall pale body, translucent fins and blue facial spotting shown, while allowing for natural variation between animals.

For broader aquarium planning, compare the fish’s needs with the body plans and care requirements represented in our marine fish collection. Treat that collection as a way to compare choices, not as a ready-made compatibility list: each proposed combination still needs screening against aquarium volume, temperament, feeding and use of the bottom area.

Build around its wild habitat

Plan the lower part of the aquarium around sand, rocks and sheltered spaces. FishBase describes adults living in silty or sandy areas of lagoons and bays, usually occupying a burrow beneath rocks. The Wikipedia species summary likewise places the fish in bays and lagoons with silt or sand substrates and rocks, at recorded depths of 3–25 m.

Those habitat details explain why open water alone is not an adequate layout. Preserve usable bottom space, provide a sand-based area and arrange rocks so the fish has access to cover. Check the layout during routine maintenance because activity near the substrate can move loose material. Rock placement must remain dependable when the fish uses the area around it.

FishBase records wild adults usually in pairs, living in burrows, and also reports aggregations over broad lagoon areas. It describes the species as monogamous. Use those observations to understand its natural social setting, while making aquarium stocking decisions around the actual tank, intended animals and their behaviour rather than assuming that a wild pair or aggregation translates directly into a fixed aquarium group.

Chalk goby and sleeper blue dot goby are additional common names associated with this species. They refer to the same Valenciennea sexguttata identified here, rather than separate colour forms or sex choices.

Hold the water inside the care range

Keep the temperature at 24–26°C, salinity at 1.020–1.025, pH at 7.9–8.3 and carbonate hardness at 8–12°dKH. The temperature range sits inside FishBase’s recorded wild range of 22–28°C and matches OATA’s aquarium guidance for gobies. Aim for stable readings within the routine ranges rather than moving repeatedly between their limits.

Maintain ammonia at zero mg per litre and nitrite at zero mg per litre. Keep nitrate from exceeding 50 mg per litre. These waste readings are active stocking and maintenance limits: test them before introducing the fish, continue monitoring them after introduction and investigate any departure from zero for ammonia or nitrite.

Use the full marine profile

• Temperature: 24–26°C.
• Salinity: 1.020–1.025.
• pH: 7.9–8.3.
• Carbonate hardness: 8–12°dKH.
• Ammonia and nitrite: zero mg per litre.
• Nitrate: up to 50 mg per litre.
• Calcium: 380–450 ppm.
• Magnesium: 1250–1350 ppm.

OATA includes calcium and magnesium in its marine goby profile, but a reef aquarium may need different parameters for more sensitive inhabitants. Assess the needs of every animal in the system together; do not alter one value in isolation while ignoring salinity, pH, hardness or the waste readings.

Record results consistently enough to notice movement before it becomes a large change. A reading is most useful when it can be compared with the aquarium’s previous stable pattern, the condition of the fish and recent stocking or feeding changes.

Use repeated results to guide action. If ammonia or nitrite rises above zero mg per litre after adding livestock or increasing food, stop further stocking, review the feeding load and check that filtration remains unobstructed. If temperature, salinity or pH begins drifting, correct the cause steadily while continuing to monitor the whole marine profile rather than reacting to one isolated reading.

Establish filtration before stocking

Use a well-established and maintained biological filter before adding the goby. The RSPCA explains that fish release toxic ammonia, which filter bacteria convert first to nitrite and then to the safer nitrate. The filter therefore has to be functioning as a biological system, not merely moving water.

OATA says a filter is essential for every goby aquarium. A marine system may use live rock with sufficient water flow, an internal or external filter, or a sump-based filter. Choose a method capable of supporting the aquarium’s whole livestock and feeding load, then maintain it so water flow is not reduced by blockage.

Check readiness in the right order

1. Confirm that the filter has matured and is operating continuously.
2. Test ammonia and nitrite and add the fish only when both are zero mg per litre.
3. Check temperature, salinity and pH against the intended routine range.
4. Increase the aquarium’s fish population slowly so its beneficial bacteria can respond to the added waste and feeding.

Adding too many fish or adding them too quickly can leave the bacterial population unable to process the increased waste. OATA describes the resulting ammonia and nitrite rise as new tank syndrome, which can make fish ill or cause death. A large aquarium offers greater environmental stability, but its volume does not replace filter maturation or controlled stocking.

A protein skimmer can help maintain water quality by removing dissolved organic waste before it breaks down into more harmful substances. Treat it as support for the biological filter and maintenance routine, not as a substitute for testing or partial water changes.

Use the first readings after introduction as a filter-capacity checkpoint. Continue testing ammonia and nitrite while the biological filter adjusts to the additional waste. Delay any further increase in livestock or feeding load if either reading departs from zero mg per litre, and keep checking until the aquarium has returned to its established pattern.

Give the adult fish enough space

Use at least 120 litres for one Sixspot goby. OATA recommends that volume for larger goby species, and the fish’s recorded adult length of 14 cm places it above the smaller-species category of under 7–8 cm. Do not apply the 40-litre recommendation for smaller gobies to this species.

Use a larger aquarium when adding other fish. OATA links increased volume with greater stability in temperature and water quality as well as the extra demands of mixed stocking. The 120-litre figure is therefore a minimum planning reference for one larger goby, not a general capacity figure for a community.

Test the aquarium plan before adding livestock

• Adult size: reserve space for a fish reaching 14 cm.
• Bottom area: retain access to sand, rock and shelter rather than filling every lower space.
• Filtration: match the filter to the full biological load and keep it mature.
• Mixed stocking: increase the aquarium beyond 120 litres and screen every intended animal.
• Water stability: confirm that temperature, salinity, pH, ammonia and nitrite remain within their routine limits.

A worked planning decision is straightforward: a 100-litre aquarium remains below OATA’s larger-goby recommendation even if the fish is shorter when it arrives. A 120-litre aquarium reaches the group minimum for one, but adding other fish calls for more space rather than treating the same volume as a complete mixed-stock plan.

Plan the permanent aquarium before purchase. Moving the fish through progressively larger aquariums is not a reason to start below the adult category, and apparent body size in a photograph does not change the 14 cm planning length.

Evaluate usable space as well as nominal volume. A tank can meet the litre figure while leaving too little open substrate if rocks, equipment or other bottom-associated animals occupy most of the lower area. Map where the sand, shelter and feeding space will be, then check that the final arrangement still supports filtration flow and routine access for waste removal.

Feed small portions twice daily

Feed twice a day, giving only what the fish can eat within a few minutes. OATA’s goby guidance says most gobies require a varied diet and warns that overfeeding can leave uneaten food to accumulate. Judge the portion by what is consumed promptly rather than by a fixed count of pieces.

For a larger goby, offer appropriately sized frozen meaty foods such as krill, mysis shrimp or enriched brine shrimp. OATA also says many gobies accept prepared diets, so suitably sized granules, flakes or sinking pellets may form part of the rotation when the individual takes them. Variety remains important; avoid relying on one food without observing whether it is being eaten.

Match food to feeding behaviour

• At each feed: offer a small amount and watch where the fish takes it.
• Within a few minutes: stop adding food once the usable portion has been eaten.
• If food is ignored: check portion size, food size and the fish’s behaviour before adding more.
• If the fish sifts sand for food: maintain a mature sand bed containing prey items and supplement it with live copepods, small frozen meaty foods or sinking pellets.
• If food remains: remove the excess through the normal waste-removal routine rather than allowing it to break down.

Some gobies obtain invertebrate food items by sifting sand, but that group behaviour should be confirmed through observation of the individual. A mature sand bed can support a larger population of prey items than a newly established one. Cultured or shop-bought live copepods can supplement those prey when sand-sifting behaviour is seen.

Watch body condition and interest in food over time. Reduced intake is one of OATA’s warning signs for fish health, while excessive food can damage water quality. The feeding decision and the filtration decision are therefore linked: increase neither food nor livestock faster than the mature filter can process the resulting waste.

Use the first week to establish a repeatable portion. Begin with a small amount of appropriately sized food, watch whether it reaches the goby and note what remains after a few minutes. Reduce the next portion if food is left behind; if the fish takes everything promptly, preserve that measured routine rather than adding extra food automatically.

Make weekly maintenance consistent

Carry out a 25% partial water change at least once every week. Schedule the 25% change weekly or more often when needed, while continuing to use test results and observations to guide the wider maintenance routine. Use a siphon during the change to remove solid waste from the gravel or substrate where it has collected.

Check the filter regularly and clean it often enough to prevent blockage. If its media needs cleaning, do not run it under the tap. Rinse it lightly in aquarium water removed during the partial water change, which reduces the loss of the established beneficial bacteria. Keep the filter operating as the aquarium’s biological support rather than cleaning it so aggressively that its bacterial population is stripped away.

Use the water change as a complete checkpoint

1. Test ammonia, nitrite, nitrate, pH and the other marine parameters you monitor.
2. Observe the fish’s swimming, breathing, colour, body condition and response to food.
3. Siphon accumulated solid waste while removing 25% of the water.
4. Rinse filter media lightly in the removed aquarium water when cleaning is needed.
5. Check filters for obstruction and clean the protein skimmer regularly to preserve its performance.
6. Record readings and observations so changes can be compared from one week to the next.

The readings and observations answer different questions. Water tests show whether the filter and maintenance routine are controlling waste; the fish’s appearance and behaviour show how it is responding. Use both rather than assuming clear-looking water has safe ammonia and nitrite levels.

A larger aquarium helps buffer environmental changes, but it still requires this routine. Weekly maintenance is also the point at which to inspect the bottom area, remove uneaten food and check whether sand has been shifted into places where it could affect equipment or bottom-dwelling animals.

Compare each checkpoint with the previous one. A rising nitrate result, repeated uneaten food or increasing solid waste indicates that feeding, stocking and removal are no longer balanced. Address the cause while preserving the established biological filter, and continue checking ammonia and nitrite at zero mg per litre rather than relying on the aquarium’s appearance.

Follow the arrival steps in order

Our delivery and Live Arrival Guarantee policy says fish are hand-bagged in pure oxygen and placed in an insulated poly box, with a heat pack when the weather calls for it. Be present to receive the parcel because live fish cannot be left unattended.

On receipt

1. Start filming while the parcel is still sealed and its outer box is visible.
2. Open the parcel the same day in one continuous take.
3. Show the fish still inside the sealed bag before anything is disturbed.
4. Float the bag for 20–30 minutes before releasing the fish.
5. Release the fish without pouring the bag water into the aquarium.

Before the parcel arrives, prepare a mature, filtered receiving aquarium within the fish’s routine marine ranges and confirm that ammonia and nitrite are zero mg per litre. Complete these checks early enough to address a water or equipment problem before the fish is released.

For a Live Arrival Guarantee claim, contact us the same day with the order number and the continuous unboxing video. The video must begin with the sealed parcel, continue through opening and show the fish in the sealed bag before release. Keeping that sequence intact allows the condition of the parcel and fish to be seen before anything is disturbed.

After release, observe the fish’s swimming, breathing, colour and use of shelter. Keep the established filtration and water-testing routine in place rather than making abrupt changes simply because the animal is new to the aquarium.

Use the first observations as a baseline for the fish’s normal behaviour in its new surroundings. Note whether it uses the sand, rocks or shelter and whether it responds at feeding time. If swimming, breathing, colour or feeding changes, test the water and compare the result with the stable readings recorded before arrival.

Respond to health changes early

Watch for changes in swimming, colour, temperament, breathing, appearance, body condition and feeding. OATA identifies hanging at the surface, sitting on the bottom or erratic swimming as changes that deserve attention. Because gobies naturally spend much of their time near sand or rock, compare the fish with its own normal posture and movement rather than treating every visit to the bottom as a problem.

Use specific signs to guide the next check

• Swimming: notice surface hanging, persistent unusual resting or erratic movement.
• Colour: look for a marked darkening or paling from the fish’s usual appearance.
• Temperament: note increased aggression or more hiding than normal.
• Breathing: watch for gill covers moving more slowly or rapidly than usual.
• Appearance: check for white spots, fluffy growths, lost fins or scales, ulcerations or bumps.
• Condition: notice an increase or decrease in body weight and overall condition.
• Feeding: treat reduced intake or a loss of interest in food as a meaningful change.

Test water quality when any of these changes appear. Check ammonia and nitrite first because both should remain at zero mg per litre, then review nitrate, temperature, salinity and pH against the aquarium’s normal readings. A water test turns a general concern into a concrete set of results that can guide the next response.

Contact us if you are concerned about the fish’s health, providing the recent water readings and a concise description of what changed. Do not choose a disease treatment from appearance alone. Continue observing the fish and protect stable filtration while the cause is assessed.

Screen every fish combination

OATA says gobies generally mix well with other fish, but it also stresses that gobies vary greatly in temperament. Treat that general tendency as the start of a compatibility check rather than a universal community-fish guarantee.

Use a larger aquarium when keeping the Sixspot goby with other fish. The 120-litre recommendation applies to one larger goby, while mixed stocking calls for additional space. Aquarium volume is only one part of the decision: check the proposed animals’ behaviour, water requirements, feeding, adult space needs and use of the lower part of the aquarium.

Check the proposed combination

• Water: every animal must fit the aquarium’s temperature, salinity, pH and hardness plan.
• Space: the aquarium must exceed the one-goby planning minimum when other fish are included.
• Temperament: assess each species and individual rather than relying on the word goby as a behaviour guarantee.
• Feeding: make sure the goby can take its food within the twice-daily routine without uneaten food accumulating.
• Bottom use: retain sand, rock and shelter for a fish associated with the substrate and burrows.

FishBase records wild adults usually in pairs and also describes lagoon aggregations. Those natural observations help explain its social setting, but aquarium grouping still needs to account for the intended individuals and available space. For a stocking and compatibility assessment, ask us with the aquarium volume, current livestock and the exact animals you intend to combine.

Observe the aquarium after any introduction. Changes in hiding, aggression, feeding or body condition are practical signals that the social plan should be reassessed alongside water quality.

Work through the screening points before treating any shared water range as sufficient. Two animals can fit the same temperature and salinity while still competing for bottom space or food. A stronger plan confirms suitable water first, then checks adult space, temperament, feeding access and the effect of each animal’s normal activity on the sand and rock layout.

Treat invertebrates and bottom corals with caution

Use caution with small invertebrates. OATA says some goby species may eat small invertebrates such as shrimp when they can fit into the fish’s mouth. That possibility is conditional rather than a universal outcome, so screen the size and type of invertebrate and do not promise that every shrimp or similar animal will be safe.

Use caution with corals that live on or near the bottom. OATA notes that sand-sifting gobies can deposit piles of sand in unwanted places. If this individual shows sand-sifting behaviour, inspect where displaced sand settles and make sure it is not accumulating over a bottom-dwelling coral.

Separate the two compatibility risks

• Predation risk: small invertebrates may be vulnerable if they fit into a goby’s mouth.
• Sand movement: a sand-sifting fish can move substrate onto animals or into places where it is unwanted.

These risks call for observation and layout planning, not a blanket statement that the species is safe with all invertebrates or all corals. Preserve a usable sand area, position bottom animals with potential sand movement in mind and watch what the fish actually does after introduction.

Reef planning also has a water-chemistry component. OATA advises that parameters may need alteration for more sensitive reef species. Set one coherent marine profile that meets the needs of the whole aquarium rather than assuming that the goby’s group ranges automatically suit every coral or invertebrate.

Other fish remain possible after individual screening, but no named fish is a universal companion. Check volume, temperament, feeding and bottom-space use together before making a mixed-stock decision.

Answer common Sixspot goby questions

How big does the Sixspot goby get?

FishBase records a maximum length of 14 cm total length. Plan the permanent aquarium around that adult figure.

What size aquarium does Valenciennea sexguttata need?

At 14 cm, it falls into OATA’s larger-goby category, for which the group guidance recommends at least 120 litres; use a larger aquarium when keeping it with other fish.

How many Sixspot gobies should I keep together?

FishBase records wild adults usually in pairs and sometimes in aggregations. For an aquarium, have the intended number and tank mates assessed together before adding more than one.

Is the Sixspot goby suitable for beginners?

Choose it only if you can maintain a mature, filtered marine aquarium, feed twice daily, carry out weekly maintenance and keep ammonia and nitrite at zero mg per litre.

What does the Sixspot goby eat?

OATA’s goby guidance recommends a varied diet; offer appropriately sized krill, mysis shrimp or enriched brine shrimp and feed only what it eats within a few minutes, twice a day.

What temperature and pH does Valenciennea sexguttata need?

Keep it at 24–26°C, the overlap of FishBase’s 22–28°C wild record and OATA’s goby guidance; OATA also gives pH 7.9–8.3, salinity 1.020–1.025 and 8–12°dKH.

Is this fish aggressive or likely to nip fins?

OATA describes goby temperament as varied, although gobies generally mix well with other fish. Screen each proposed combination instead of treating that general tendency as a guarantee.

Which animals can this fish live with?

Other fish may be considered after screening. OATA warns that some gobies may eat small invertebrates that fit into their mouths and that sand sifters can deposit sand on bottom corals.

How does this fish arrive alive in the UK?

Start filming the sealed parcel before opening it, show the fish in the sealed bag, then float the bag for 20–30 minutes before release; Tropical Fish Co’s policy also requires someone to receive the parcel.

Check the care references

• FishBase: Valenciennea sexguttata — scientific identity, family, distribution, habitat, wild temperature record, behaviour and maximum length.
• Wikipedia: Valenciennea sexguttata — common names and a concise summary of the species’ natural habitat and range.
• OATA: How to look after gobies — aquarium water, space, feeding, filtration, maintenance, observation and compatibility guidance for gobies.
• Tropical Fish Co delivery and Live Arrival Guarantee policy — packing, receipt, unboxing video and acclimatisation procedure.
• RSPCA aquarium welfare guidance — biological filtration and the processing of ammonia, nitrite and nitrate.