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Four-Eyed Fish

Anableps anableps

Brackish South America

A fascinating surface-dwelling livebearer possessing divided eyes adapted to see simultaneously above and below the water. Highly active in groups, they need a shallow tank with huge surface area, brackish conditions, and a tightly fitting lid to prevent powerful leaps.

Also called: Largescale foureyes, Foureye, Foureyed fish, Four-eyes.

25 cm adult length, drawn to scale. torpedo 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.
Brackish species. Needs a little salt in the water, below full marine strength. It will not mix with most freshwater fish.

Try it in the planner Opens a tank sized to its minimum with 4 fish added.

What it needs

ItemValueBecause
Adult length 25 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 300 L, at least 150 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 40 L estimated What each further fish adds once the minimum is met.
Waste load Class 3 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 7.5 to 8.5 Compared with tankmates in the Water check.
Hardness GH 10 to 25, KH 8 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 At least 4, ideally 6 Kept alone or in small numbers it hides, fades or turns on tankmates.
Temperament Peaceful Not territorial.
Swims in Upper water Fish that use different levels share a tank more easily.
Lifespan About 8 years A fish is a long commitment.
Experience Some experience helps 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

Four-Eyed Fish is an carnivore that swims in the upper water. It is safe with plants. Give it some cover. It will eat fish small enough to swallow.

Tankmates

Works with

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

Depends

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.