Identity and search names

Common name
Paradise fish
Scientific name
Macropodus opercularis
Other names
Paradise fish, Paradise gourami, Macropodus opercularis
Category
Freshwater fish
Group
Bettas and gouramis
Origin
East Asian lowland waters, including China, Taiwan and northern Vietnam; introduced populations occur elsewhere
Review outcome
PASSED

Environment and housing

Environment
Freshwater
Care level
Intermediate
Adult size
Usually 8–11 cm total length
Expected lifespan
About 6–8 years
Minimum housing
At least 120 L for one male with suitable companions; larger for a managed pair or group
Temperature
16–26 °C
pH
6.0–8.0
Hardness or minerals
Soft to hard
Salinity
Freshwater
Lighting
Moderate with dense planted cover
Social structure
Usually keep one adult male per aquarium; pair or group arrangements require substantially more space and active monitoring
Placement or swimming zone
Upper and middle water with surface access
Temperament
Territorial and potentially aggressive, particularly adult males
Compatibility
Use robust short-finned fish that tolerate the same cooler range; species-focused housing is often safest
Habitat structure
Densely planted aquarium with gentle flow, open surface access, seasonal rather than permanently tropical heat and a secure lid

Feeding and nutrition

Diet
Aquatic and terrestrial invertebrates, crustaceans and varied high-quality prepared foods
Feeding frequency
Feed measured varied meals once or twice daily and avoid obesity

Breeding and reproduction

Breeding or reproduction
The male builds and guards a surface bubble nest. Remove the female if she is attacked after spawning and separate the male once fry become free-swimming.
Parental care
Male guards nest and eggs until fry become free-swimming

System demands

Filtration
Use mature biological filtration sized for the full adult group and feeding load, with intake protection where juveniles, long fins or small fish are present. Provide steady turnover without preventing normal swimming or resting.
Aeration
Maintain strong surface gas exchange and stable dissolved oxygen. Increase aeration during warm weather, medication, transport recovery, breeding crowding or any ammonia or nitrite event.
Maintenance
Test ammonia, nitrite and nitrate, remove waste from feeding and shelter zones, and perform regular temperature- and chemistry-matched water changes before nitrate or dissolved organics accumulate.

Detailed husbandry

Identity scope
This profile applies to Macropodus opercularis. Domestic colour forms remain the same species, but introduced populations must not be used to justify release.
Adult size and space
Usually 8–11 cm total length. At least 120 L for one male with suitable companions; larger for a managed pair or group. Plan around adult dimensions, activity, social structure, aggression and waste production rather than sale size.
Social structure
Usually keep one adult male per aquarium; pair or group arrangements require substantially more space and active monitoring
Placement or swimming zone
Primary zone: Upper and middle water with surface access. Keep that zone usable for movement, feeding and refuge.
Feeding ecology
Aquatic and terrestrial invertebrates, crustaceans and varied high-quality prepared foods
Feeding plan
Feed measured varied meals once or twice daily and avoid obesity
Water stability
Maintain 16–26 °C; pH 6.0–8.0; hardness/minerals: Soft to hard. Stable oxygenation and nitrogen-cycle control matter more than chasing one exact number.
Adult projected load
Plan capacity for Usually keep one adult male per aquarium; pair or group arrangements require substantially more space and active monitoring at the documented adult size (Usually 8–11 cm total length) in At least 120 L for one male with suitable companions; larger for a managed pair or group. Include feeding intensity, territorial behaviour and breeding growth rather than counting sale-size juveniles.
Filtration
Use mature biological filtration sized for the full adult group and feeding load, with intake protection where juveniles, long fins or small fish are present. Provide steady turnover without preventing normal swimming or resting.
Aeration
Maintain strong surface gas exchange and stable dissolved oxygen. Increase aeration during warm weather, medication, transport recovery, breeding crowding or any ammonia or nitrite event.
Maintenance
Test ammonia, nitrite and nitrate, remove waste from feeding and shelter zones, and perform regular temperature- and chemistry-matched water changes before nitrate or dissolved organics accumulate.
Habitat structure
Densely planted aquarium with gentle flow, open surface access, seasonal rather than permanently tropical heat and a secure lid
Compatibility plan
Use robust short-finned fish that tolerate the same cooler range; species-focused housing is often safest
Breeding plan
The male builds and guards a surface bubble nest. Remove the female if she is attacked after spawning and separate the male once fry become free-swimming. Parental care: Male guards nest and eggs until fry become free-swimming.
Quarantine
Quarantine new fish in a separate cycled aquarium with dedicated equipment. Match temperature and mineral chemistry gradually, confirm feeding and normal respiration, and never add transport water to the established aquarium.
Welfare checks
Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Cool-water tolerance does not make this a harmless community fish. Male aggression and chronic over-heating are common welfare failures.
Biosecurity and release
Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.
Main risk
Cool-water tolerance does not make this a harmless community fish. Male aggression and chronic over-heating are common welfare failures.
Overridable warnings
Cool-water tolerance does not make this a harmless community fish. Male aggression and chronic over-heating are common welfare failures. Any override must still preserve adult space, social welfare, stable chemistry, oxygen and filter capacity.

Welfare and risk

Welfare checks
Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Cool-water tolerance does not make this a harmless community fish. Male aggression and chronic over-heating are common welfare failures.
Main warning
Cool-water tolerance does not make this a harmless community fish. Male aggression and chronic over-heating are common welfare failures.
Biosecurity
Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.

Sources

Source note

Current identity or scope, husbandry, system-demand, welfare and Australian biosecurity evidence checked; active retired-source links removed; all AquaNexus wording is original.

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