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Tench

Tinca tinca

Freshwater Europe Usually captive bred

A robust, thickset coldwater cyprinid with olive-green or ornamental golden coloration and tiny red eyes. It roots gently in soft substrate searching for benthic invertebrates. It thrives best in well-aerated outdoor ponds or very spacious, unheated indoor aquaria with deep sand beds.

Also called: Doctor fish, Doctor-fish, Green tench.

40 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 2 fish added.

What it needs

ItemValueBecause
Adult length 40 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 150 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 10 to 22 C Stock sharing a tank need overlapping ranges.
pH 6.8 to 8 Compared with tankmates in the Water check.
Hardness GH 8 to 20, KH 6 to 14 Degrees of general and carbonate hardness.
Flow Low Low-flow fish are stressed in a strong current.
Light Dim Matched to the lighting class on the needs sheet.
Group size At least 2, ideally 5 Kept alone or in small numbers it hides, fades or turns on tankmates.
Temperament Peaceful Not territorial.
Swims in Near the bottom Fish that use different levels share a tank more easily.
Lifespan About 15 years A fish is a long commitment.
Experience Suits a first tank A guide to how forgiving the species is of mistakes.

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

Tench is an omnivore that swims in the lowest part of the tank. It leaves most plants alone. Give it some cover. It digs, so anchor plants and keep hard rock off loose sand.

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.