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Gnathochromis permaxillaris

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Gnathochromis permaxillaris is a species of African fish in the family Cichlidae.

Aquarium hobby

Experience: Intermediate

FamilyCichlids

Adult lengthup to 5.9 in

WaterFreshwater

Care at a glance

Species-specific aquarium care

Tank: At least 30 in long and 12 in front to back for one adult (adults commonly reach about 5.9 in / 15 cm).
Water: Freshwater.
Temperature: 75–79°F (range recorded for this species).
Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.

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

Tank: a base of at least 47 × 12 in (roughly 29 US gallons); space needed is rated “large tank”.
Water: hard, alkaline water, 72–81 °F, pH 7.5–9, 8–25 dGH.
Difficulty: Easy (Seriously Fish rating).

Short excerpts from the species profile:

Setup: “Set up the aquarium with large piles of rocks arranged to form caves, large areas of open water for swimming and a sandy substrate.”
Diet: “Live and frozen foods should comprise a large proportion of the diet.”
Tankmates: “Not a particularly aggressive fish and should not be housed with rowdy species such as Mbuna.”
Breeding: “Not often bred in aquaria and details are scarce.”

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

Group care guide

Lake Tanganyika cichlids

Applies to most species in this group. Habitat: Rocky reefs, shell beds and sand of Lake Tanganyika. Individual species can differ, so compare with the species numbers above and the linked sources.

Housing & setup

Use species-specific alkaline-water parameters and stable, well-oxygenated conditions. For N. multifasciatus, Seriously Fish gives pH 7.5–9.0 and general hardness 8–25 dGH.
Shell-dwellers need beds of empty snail shells; rock-dwellers like Julidochromis need stacked rockwork; Tropheus need large groups and spacious tanks.

Sources 117 119 164 118 256 273

Climate & lighting

Water

76–81°F

Sources 117 119 164 118 256 273

Diet

Tropheus moorii needs a vegetable-based staple with small suitable live/frozen supplements. Other Tanganyikans need their own feeding plan; shell-dweller and predator diets differ.

Sources 117 119 164 118 256 273

Social life

Often pair- or colony-forming and territorial; research each genus.

Sources 117 119 164 118 256 273

Health watch

Tropheus are prone to bloat on rich foods; sudden water changes stress Tanganyikans.

Sources 117 119 164 118 256 273

Understanding the animal

About this animal

It is endemic to relatively deep waters in Lake Tanganyika in the countries of Burundi, the Democratic Republic of the Congo, Tanzania, and Zambia. It is widespread in the lake, but occurs in low densities.

Quoted from the Wikipedia article “Gnathochromis permaxillaris” (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.
Water it lives in	Freshwater, 75–79 °F (24–26 °C).
Climate	Tropical climate.
Behavior to plan for	Breeding: external brooders, biparental parental care.

What this means for care

Keep water within its wild range, 75–79 °F.
Parents guard eggs or young, so expect territorial behavior when breeding.

FishBase species summary: Gnathochromis permaxillaris

Native climate (measured)

Warm-season highs	about 86°F (up to 90°F in the hottest sampled areas)
Cool-season lows	about 62°F (down to 54°F in the coldest sampled areas)
Average temperature	67–79°F across sampled records
Relative humidity	57–74% on average (driest month about 60%)
Rainfall	about 1055 mm a year

Measured at 15 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	Gnathochromis permaxillaris is a species of African fish in the family Cichlidae. It is endemic to relatively deep waters in Lake Tanganyika in the countries of Burundi, the Democratic Republic of the Congo, Tanzania, and Zambia. It is widespread in the lake, but occurs in low densities. It has been recorded as deep as 200 m, even in waters virtually devoid of oxygen. — 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
Reproduction	Males and females are mouthbrooders. — FishBase

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 sources5.9in

FishBase 1645.9

Seriously Fish species profiles 1675.9

Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.

Water temperature

Average of sources73.5–80°F

FishBase 16475–79

Seriously Fish species profiles 16772–81

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

pH

Reported7.5–9

Seriously Fish species profiles 1677.5–9

Water hardness

Reported8–25dGH

Seriously Fish species profiles 1678–25

Minimum tank footprint

Reported47in

Seriously Fish species profiles 16747

Seriously Fish recommends a tank base of at least 47 × 12 in (about 29 US gallons).

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.
Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Seriously Fish — Neolamprologus multifasciatus Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
Seriously Fish — Tropheus moorii Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.