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Rio Pearlfish

Nematolebias whitei

Freshwater South America Usually captive bred

A classic annual killifish from temporary coastal pools near Rio de Janeiro. Males display glittering iridescent spots over a dark body with delicate fins. Because of its brief life cycle, keep this species in species-only breeding setups with peat substrate for egg collection and cooler, soft water.

Also called: Rio pearlfish, White's pearlfish.

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

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

What it needs

ItemValueBecause
Adult length 7 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 45 L, at least 45 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 10 L estimated What each further fish adds once the minimum is met.
Waste load Class 2 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 18 to 24 C Stock sharing a tank need overlapping ranges.
pH 6 to 7.2 Compared with tankmates in the Water check.
Hardness GH 4 to 10, KH 2 to 6 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 Single fish is fine Not a schooling species.
Temperament Peaceful Territorial: weak.
Swims in Near the bottom Fish that use different levels share a tank more easily.
Lifespan About 1 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

Rio Pearlfish is an carnivore that swims in the lowest part of the tank. It is safe with plants. Give it plenty of cover. It digs, so anchor plants and keep hard rock off loose sand.

Tankmates

Works with

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.