Empire Gudgeon (Hypseleotris compressa)

Choose the Empire Gudgeon for a calm, planted community

The Empire Gudgeon (Hypseleotris compressa) is an Australian sleeper goby, a member of the family Eleotridae. Unlike the bottom-hugging gobies, sleepers have separate pelvic fins rather than a sucker disc, and this gudgeon lives among plants and submerged branches rather than on open sand. The species name means compressed, for its deep, flattened body.

For most of the year it is an understated fish. The Australian Museum describes females as brown to golden with whitish undersides. In the breeding season the males transform: the head and belly turn bright orange-red, and the dorsal and anal fins become red-orange at the base with a dark band near the edge and a pale margin. A group of coloured males displaying to each other is the main attraction of this fish.

Know the names

Seriously Fish gives the range as northern and eastern Australia and southern New Guinea: in Australia from the Pilbara and Kimberley regions of Western Australia, around the northern and eastern coasts, south to the Towamba River system in New South Wales. FishBase adds that adults live in the lower reaches of rivers, in flowing or still water among aquatic plants or submerged branches, while juveniles are often found in fast water or brackish estuaries.

Browse our gobies, gudgeons and mudskippers, including the smaller Peacock Gudgeon, the related Mogurnda gudgeons such as the Purple Spotted Gudgeon, or our wider community tank fish.

Check what you receive

One purchase supplies one live Empire Gudgeon in the standard size we stock. That is a young or subadult fish, so expect the quieter colours of a female or non-breeding male on arrival. Seriously Fish notes that males intensify in colour when they are ready to spawn, so the orange-red breeding dress appears once the fish are mature, settled and well fed. The photographs show the species, not the individual fish; size, colour and pattern vary from fish to fish.

The sex is not selected or guaranteed. Young gudgeons are not easy to sex, and the clearest sign, the male's breeding colour, appears only later.

Plan the pair or group

• A pair: Seriously Fish says the species is best kept in a pair.
• Several fish: buy three or four to give a good chance of at least one male and one female, then rehome extra males if they squabble.
• Territories: males defend a territory when they spawn, so every male needs its own patch of cover.

Read our delivery and Live Arrival Guarantee policy before ordering, and have the aquarium matured and tested first.

Plan the aquarium around the adult size

Seriously Fish recommends a base of at least 80 x 30 cm, about 72 litres, and gives the maximum size as 120 mm standard length; FishBase gives the same 12 cm maximum and a common length of 5 cm. OATA's freshwater goby care sheet asks for at least 80 litres for a group of the larger gobies and adds that bigger tanks are more stable. Use those as the minimum for a pair, and go larger for a group or a mixed community so that each male can hold a separate territory.

Use a three-step space check

Our stocking calculator helps you add up adult sizes, and our guide to the best fish for a 100-litre tank shows how a community of this size fits together.

Furnish it with plants, wood and sight breaks

Seriously Fish asks for plenty of hiding places and cover to break up lines of sight, so that weaker fish can get away from dominant ones. That matches the wild habitat FishBase describes, among aquatic plants and submerged branches. OATA recommends fine gravel or sand, heavy planting with live plants, especially when several males are kept, and rounded pebbles and stones; where live plants are not used, wood, plant pots or caves provide the cover.

Fit a cover. OATA says a lid is essential for gobies because they can jump when startled, and a displaying male chasing a rival is easily startled.

Divide the footprint by purpose

Seriously Fish notes that eggs are laid on a pre-cleaned solid surface such as a rock, driftwood or even the glass, so flat stones near cover give a breeding pair an obvious site.

Keep stable water in the middle of a wide range

The Empire Gudgeon is one of the most tolerant aquarium fish there is. In the wild it moves between rivers, estuaries and the sea, and FishBase records that it tolerates salinity equal to seawater, temperatures up to 35°C and a pH from 5.0 to 9.1. The sources still differ on the details, so keep the water steady in the middle of the overlap rather than near any extreme.

Salt is not needed. Seriously Fish explains that adults live and spawn in fresh water; it is the larvae and juveniles that use the sea and estuaries.

Match your tap water first

Most UK tap water, soft or hard, sits within this fish's range once it is dechlorinated, so there is rarely any need to adjust it. What matters is stability: make every water change at the same temperature and from the same source. Our water chemistry guide explains the readings, and the water matcher checks your tap water against this fish.

Filter gently and keep the water clean

Seriously Fish says the filtration does not need to be strong and that an air-powered sponge filter is ideal; in a larger community tank an external or internal filter with a gentle, spread-out return works as well. OATA calls a filter essential for gobies and asks for at least a 25% water change every week. Our guide to aquarium filtration explains how to size and maintain one.

Follow a weekly routine

1. Test ammonia, nitrite, nitrate, pH and temperature, more often while the tank is new.
2. Siphon the sand around the plants and remove leftover food.
3. Change at least 25% of the water with dechlorinated water at the same temperature.
4. Squeeze sponge filters in removed tank water when the flow drops, never under the tap.
5. Trim fast-growing plants so open swimming and feeding space remains.

Feed small meaty foods once a day

In the wild the Empire Gudgeon eats small invertebrates. FishBase lists micro-crustaceans, mosquito larvae and algae, and the Australian Museum adds that it grazes on algae and detritus as well as eating water fleas and insect larvae. In the aquarium, Seriously Fish recommends small live or frozen foods such as bloodworm, mosquito larvae, brine shrimp, daphnia and mysis, and notes that dried foods are normally accepted too.

OATA's guidance for gobies is to feed once a day, only what is eaten within a few minutes. Conditioning a pair for breeding is the one time to feed more live and frozen food.

Build one measured meal

• Most days: frozen mysis or frozen daphnia, thawed in a little tank water.
• For variety: freeze-dried brine shrimp, soaked before feeding.
• Dried staple: small carnivore pellets sized to the gudgeon's mouth.
• Quantity: what the fish finish within a few minutes; remove the rest.

If faster tank mates take everything at the surface, drop some food near the gudgeons' cover so they get their share.

Introduce it calmly and watch the first week

OATA advises checking that ammonia and nitrite read zero before adding fish, adding new fish slowly so that the filter bacteria keep pace, and watching water quality closely during the first week. Our guide to acclimatising new fish covers the steps in detail.

Use OATA's floating-bag method

1. Switch off the aquarium lights and keep the bag out of bright light.
2. Float the sealed bag for 10 minutes to match the temperature.
3. Add small amounts of aquarium water to the bag over up to 20 minutes.
4. Net the fish into the aquarium, keeping the bag water out.
5. Leave the lights off for the rest of the day.

Choose tank mates of a similar size

Seriously Fish's advice is to choose tank mates carefully, because males defend their territory during spawning. The Empire Gudgeon is not a large predator, but its wild diet of small crustaceans and insect larvae means that shrimplets and fish fry are likely to be eaten, and very small fish are at risk from a 12 cm adult. Pick calm fish of a similar size that use the upper and middle water, and give the gudgeons the planted lower half.

Screen each tank mate

Rainbowfish make an Australian-themed community; see our full rainbowfish range. Our tank mates tool checks size and temperament before you buy.

Breed it only as a specialist project

Empire Gudgeons spawn readily once mature, but raising the young is rarely achieved. Seriously Fish explains that the species is amphidromous: adults spawn in fresh water, the larvae drift to the sea, and young fish grow up around the coast and in estuaries before returning to rivers. The newly hatched larvae are tiny, have no working gut or rayed fins at first, and cannot even take infusoria-type foods.

Follow the spawning sequence

1. The male colours up, courts a female and defends a territory.
2. The female lays up to 3,000 tiny eggs on a cleaned rock, piece of wood or the glass.
3. The male drives the female away and guards the eggs alone.
4. The eggs hatch in about 24 hours according to Seriously Fish, or 10 to 14 hours according to FishBase.
5. The larvae drift in open water; OATA notes that goby fry produced in home aquariums are unlikely to survive.

Watch the group and act on changes

Empire Gudgeons are hardy, so most problems come from bullying between males, food going to faster fish, or a sudden change in water. Look at the fish every day at feeding time.

Pair each sign with an action

Answer Empire Gudgeon buying questions

What is an Empire Gudgeon?

Hypseleotris compressa is a sleeper goby (family Eleotridae) from northern and eastern Australia and southern New Guinea. It is also called the carp gudgeon, empire fish and northern carp-gudgeon. Females are brown to golden; breeding males turn orange-red on the head and belly and develop red-orange fins edged with dark and pale bands.

How big does an Empire Gudgeon grow?

About 12 cm. Seriously Fish and FishBase both give a maximum of 12 cm standard length, and FishBase gives a common length of 5 cm.

What size tank does it need?

An aquarium with a base of at least 80 x 30 cm, about 72 litres, as Seriously Fish recommends. Give more room for a group or a mixed community, so that males can hold separate territories.

Does it need brackish water?

No. Adults live and spawn in fresh water. Young fish develop in estuaries and the sea, and the species tolerates salinity up to that of seawater, but an aquarium for adults should be freshwater.

What does it eat?

Small live, frozen and dried foods. In the wild it eats tiny crustaceans, insect larvae and some algae; in the aquarium, bloodworm, mosquito larvae, brine shrimp, daphnia and mysis, plus dried foods, which it normally accepts.

Is the Empire Gudgeon a community fish?

Yes, with care. It is calm with fish of similar size, but males defend a territory when they spawn, and its wild diet of small crustaceans means shrimplets and fry are likely to be eaten.

Should I buy a pair?

Seriously Fish says it is best kept in a pair. Because sex cannot be chosen at our size, buying three or four gives you the best chance of at least one male and one female.

Can I breed Empire Gudgeons?

Adults spawn readily once mature, laying up to 3,000 tiny eggs that the male guards. Raising the fry is rarely achieved, because the larvae normally develop in the sea and are too small for ordinary first foods.

Consult the care references

• Seriously Fish: Hypseleotris compressa, Empire Gudgeon: Empire gudgeon profile: classification and former names, range from the Pilbara and Kimberley around northern and eastern Australia to New South Wales and southern New Guinea, amphidromous life cycle, 120 mm SL, 80 x 30 cm tank, cover, sponge filtration, water values, foods, pair keeping, male territory and the spawning sequence.
• FishBase: Hypseleotris compressa, Empire gudgeon: Hypseleotris compressa: maximum 12.0 cm SL, common length 5 cm, temperature, salinity and pH tolerance, adult and juvenile habitats, wild diet, spawning, egg number and hatching time, IUCN Least Concern.
• Australian Museum: Empire Gudgeon, Hypseleotris compressa: Australian Museum species page: other common names, size, female and breeding-male colours, habitat, salinity and temperature tolerance, diet and breeding.
• OATA: How to look after freshwater gobies and blennies: UK trade guidance for freshwater gobies: group water values, tank size for small and larger species, substrate, cover, lid, feeding, weekly maintenance and acclimatisation.
• Tropical Fish Co delivery policy: current dispatch days and Live Arrival Guarantee terms.