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Three-Spot Petrochromis

Petrochromis polyodon

Freshwater Lake Tanganyika, Africa

A robust, highly specialised rock-grazing cichlid endemic to Lake Tanganyika. Endowed with broad lips and comb-like teeth, it relentlessly rasps epilithic algae. It is notoriously hyper-aggressive in captivity, demanding huge aquariums, strong buffering, and crowded colony housing to disperse territorial rage.

20 cm adult length, drawn to scale. deep body.

Outgrows a typical home tank. Check this fish against the adult size above before buying a juvenile. The minimum shown is the least it is kept in for good, not a comfortable size.

Try it in the planner Opens a tank sized to its minimum with 1 fish added.

What it needs

ItemValueBecause
Adult length 20 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 600 L, at least 180 cm long estimated The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish 60 L estimated What each further fish adds once the minimum is met.
Waste load Class 4 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 24 to 28 C Stock sharing a tank need overlapping ranges.
pH 8.2 to 9.2 Compared with tankmates in the Water check.
Hardness GH 12 to 25, KH 10 to 18 Degrees of general and carbonate hardness.
Flow Medium Low-flow fish are stressed in a strong current.
Light Bright Matched to the lighting class on the needs sheet.
Group size Single fish is fine Not a schooling species.
Temperament Aggressive Territorial: strong.
Swims in Near the bottom Fish that use different levels share a tank more easily.
Lifespan About 10 years A fish is a long commitment.
Experience Experienced keepers only A guide to how forgiving the species is of mistakes.
Jumps Yes Keep the tank covered.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Three-Spot Petrochromis is an herbivore that swims in the lowest part of the tank. It eats or uproots plants, so choose hard-leaved species or none. Give it plenty of cover.

Tankmates

Works with

No close matches in the data. Check the pair tool.

Depends

Nothing flagged.

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.