Fallax killifish

Fundulopanchax fallax

Also known as CL 98 killi, Deceptive killifish

FreshwaterFish

Care at a glance

Temperature: 68–77°F (20–25°C)
pH: 5.5–7.0
Adult size: 3.5 in (9 cm)
Minimum tank: 14 gal (54 L)
Temperament: Mostly peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Coastal Cameroon
Family: Nothobranchiidae

Overview

The fallax killifish is one of the larger and more striking killis in this group, kept as a single pair or a harem of one male to two or more females. It swims through the middle and lower water and is a strong jumper, so a tight cover is a must. It is mostly peaceful for its size but may eat much smaller fish, so keep it in a species tank or with calm, similar sized company. Feed well on meaty live and frozen foods such as bloodworm, brine shrimp, daphnia, and chopped foods, plus some dry. A pair needs a tank of at least about 54 liters, and a harem of this big, active fish appreciates considerably more.

In the wild

The fallax killifish lives in swampy, slow moving streams along the coast of Cameroon, soft, tea-dark water shaded by forest and littered with leaves. Give it a dim, planted tank with a dark base, wood, and leaf litter, and keep the flow gentle. Hold the water soft and acidic to neutral, about pH 5.5–7.0, and warm at 20–25 C, topping up the tannins with leaves or peat to hold the stained look it lives in.

Good to know

Fundulopanchax fallax is a member of the family Nothobranchiidae and reaches about 9 cm, making it one of the bigger killifish a hobbyist is likely to keep. It is a semi-annual soil spawner whose eggs are buried and given a damp rest before hatching, a routine that puts breeding at a moderate level. The species name fallax is Latin for deceptive, given for how easily it has been confused with its relatives.

Did you know

Its name is almost an admission: fallax means deceiver, and the fish earned it by being misidentified so often that being hard to tell apart became part of its formal description.

Tank mates

Fallax killifish is a mostly peaceful, social species that keeps to the middle. These picks match on water type, temperature, pH, size and temperament.