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No federal permit to keep

Blue discus

Symphysodon aequifasciatus

Also known as Brown Discus

Fishes › Cichlids (Cichliformes) › Cichlidae (Cichlids)

Symphysodon aequifasciatus, the blue discus or brown discus, is a species of cichlid native to rivers of the eastern and central Amazon Basin downriver from the Purus Arch.

Aquarium hobby

Experience: Advanced

FamilyCichlids

Adult lengthup to 5.5 in

WaterFreshwater

Care at a glance

Species-specific values

Values researched for this exact species. Where they differ from the group guide below, follow these. Air, surface and water temperatures are listed separately, and each source is kept as published rather than averaged.

Tank dimensions recommendation	length: 120 cm; width: 45 cm; height: 45 cm Few juveniles OR one breeding pair of adults; not an adult group minimum.	285
Wild standard length	140 mm SL Wild size statement; not a captive strain maximum.	285

Species-specific aquarium care

Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 5.4 in / 13.7 cm).
Water: Freshwater.
Temperature: 79–86°F (range recorded for this species).
pH: 5–8.
Hardness: 0–12 dGH.
Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
Diet: Eats a varied diet: mix quality prepared foods with frozen and live foods. FishBase classes it as a carnivore.

Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.

Care guide

Species care notes

Behaviour: a shoaling fish best kept in a group of six or more; suited to a community tank.
Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

Setup: “Many Discus fanatics choose to go down the heavily planted route which can be particularly beneficial to Symphysodon aequifasciatus due to the amount of cover afforded by such a setup.”
Diet: “Wild fish feed mainly on zoplankton, insects and other small invertebrates.”

From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167

Group care guide

Discus

Applies to most species in this group. Habitat: Floodplain lakes of the Amazon. Individual species can differ, so compare with the species numbers above and the linked sources.

Housing & setup

Large, tall tanks (55 gallons+ for a group), soft acidic water (pH 5.5–7) and very warm temperatures (82–88 °F).
Frequent, large water changes; many keepers change 30–50% several times a week.

Sources 117 119 164

Climate & lighting

Water

82–88°F

Sources 117 119 164

Diet

High-quality discus pellets, frozen bloodworms and beefheart mixes, several small feedings daily for juveniles.

Sources 117 119 164

Social life

Groups of five or more; shy and peaceful.

Sources 117 119 164

Health watch

Hexamita (hole-in-the-head) and stress diseases in poor water; buy from reputable breeders.

Sources 117 119 164

Understanding the animal

About this animal

This discus is found in black-, clear- and whitewater, but its preference for lentic habitats such as floodplains and flooded forests means that the whitewater it inhabits contain little suspended material (unlike main sections of whitewater rivers). It is largely restricted to water with a high temperature of 25–32 °C (77–90 °F) and a pH of 5.2–7.7.

Quoted from the Wikipedia article “Symphysodon aequifasciatus” (CC BY-SA 4.0) 174

In the wild

From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.¹

Where it lives	Lives in freshwater. Uses both the bottom and open water. In deep, rocky areas in crevices and among roots. Normally in schools, but territorial during breeding season. Feeds on insect larvae, insects, and planktonic invertebrates. Aquarium keeping: in groups of 5 or more individuals; keep pairs in small tanks for breeding; minimum aquarium size 120 cm.
Water it lives in	Freshwater, 79–86 °F (26–30 °C), pH 5–8, hardness 12 dH.
Climate	Tropical climate.
Behavior to plan for	Breeding: clutch tenders.

What this means for care

Keep water within its wild range, 79–86 °F.

FishBase species summary: Symphysodon aequifasciatus

Native climate (measured)

Warm-season highs	about 90°F (up to 92°F in the hottest sampled areas)
Cool-season lows	about 71°F (down to 68°F in the coldest sampled areas)
Average temperature	79–81°F across sampled records
Relative humidity	83–85% on average (driest month about 80%)
Rainfall	about 2418 mm a year

Measured at 32 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

From the sources

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

Overview	Symphysodon aequifasciatus, the blue discus or brown discus, is a species of cichlid native to rivers of the eastern and central Amazon Basin downriver from the Purus Arch. This discus is found in black-, clear- and whitewater, but its preference for lentic habitats such as floodplains and flooded forests means that the whitewater it inhabits contain little suspended material (unlike main sections of whitewater rivers). It is largely restricted to water with a high temperature of 25–32 C and a pH of 5.2–7.7. — Wikipedia (community-edited)
Where it lives	Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase
Biology	In deep, rocky areas in crevices and among roots. Normally in schools, but territorial during breeding season. Feeds on insect larvae, insects, and planktonic invertebrates. — FishBase
History and naming	The taxonomy is disputed, but FishBase follows a review of the genus from 2006. In 2007 it was suggested that the correct scientific name of the blue/brown discus is S. haraldi, whereas S. aequifasciatus is the correct name for the green discus. — Wikipedia (community-edited)

Data and studies

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Adult length

Average of sources5.5in

FishBase 1645.4

Seriously Fish species profiles 1675.5

Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.

Water temperature

Reported79–86°F

FishBase 16479–86

Range the species tolerates in nature; aim for the middle.

pH

Reported5–8

FishBase 1645–8

Water hardness

Reported0–12dGH

FishBase 1640–12

Veterinary & husbandry research

Intriguing evidence of translocations in Discus fish (Symphysodon, Cichlidae) and a report of the largest meiotic chromosomal chain observed in vertebrates Gross MC et al., Heredity 2009
Cryptobia iubilans infection in juvenile discus Yanong RP et al., Journal of the American Veterinary Medical Association 2004
Isoenzyme electrophoretic patterns in discus fish (Symphysodon aequifasciatus Pellegrin, 1904 and Symphysodon discus Heckel, 1840) from the Central Amazon Silva CA et al., Genetics and molecular research: GMR 2008
Effect of increasing lipid levels on liver metabolism, intestinal morphology and production performance of discus fish (Symphysodon aequifasciatus) Santos RFB et al., Brazilian journal of biology = Revista brasleira de biologia 2025

Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. See all 5 on PubMed → 170

Federal legal snapshot

No federal permit to keep

No federal law singles out this species for private keepers. State and local rules still apply.

State law decides most of it. Each state sets its own permits and bans for exotic, native, venomous and dangerous animals, and cities and counties can be stricter. Find your state agency →

Not covered by the Animal Welfare Act

The Act only covers warm-blooded animals. Reptiles, amphibians, fish and invertebrates have no federal care standards, even at licensed facilities; state and local rules may still apply.

Kept in captivity?

Every species on this site needs evidence that people actually keep it. For this one:

Has a Seriously Fish aquarium species profile
FishBase records it in the aquarium trade (Aquarium=commercial; AquariumFishII=based mainly on breeding; aquarium reproduction record)
85 iNaturalist observations of captive animals

Sources for this sheet

FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.