TankBud

Constanciae killifish

Simpsonichthys constanciae

Also known as Featherfin pearlfish

FreshwaterFish

Constanciae killifish (Simpsonichthys constanciae)
The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature
68–77°F
20–25°C
pH
5.5–7.0
Adult size
2.4 in
6 cm
Minimum tank
11 gal
40 L
Temperament
Mostly peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Middle
Diet
Carnivore
Difficulty
Medium
Breeding
Egg burier · Medium
Rarity
Rare
Family
Rivulidae
Origin
Coastal lowlands, Rio de Janeiro state, Brazil

Overview

The Constanciae killifish is a small, seasonal killifish that does best in a soft-water species tank. It is a step up from the easiest fish.

Did you know

The Constanciae killifish lays eggs that outlast the pool it lives in. A breeding pair dives into the soft bottom to spawn. The buried eggs survive months of drought in damp substrate, and the fry emerge with the next rains.

Caring for the Constanciae killifish

Keep Constanciae killifish as a pair or a small group in a tank of their own. A tank of at least 11 gal (40 L) is enough for a pair or trio. Plant it with fine plants over a dark substrate or peat, and add leaf litter for cover. The cover breaks up sight lines between the males.

Give them soft, gently cool water at 68 to 77°F (20 to 25°C), with an acidic to neutral pH of 5.5 to 7.0. Feed small live and frozen foods such as daphnia, brine shrimp, grindal worm and frozen bloodworm. These suit them far better than dry flake.

Males are mostly peaceful, but they display and spar with each other. Constanciae killifish are easily outcompeted, and they show best among their own kind. Choose tank mates with caution, keeping to small, calm, soft-water fish, or none at all.

Males carry the fins and pattern of a pearlfish. Constanciae killifish bury their eggs in the bottom, and breeding them is moderately difficult. Spawn a pair over a peat medium, then give the eggs a dry resting period before they hatch.

Good to know

The Constanciae killifish, Simpsonichthys constanciae, belongs to the family Rivulidae, the New World killifishes. It is an annual fish, and in the wild the adults die as their pool dries out.

In the wild

The Constanciae killifish lives in seasonal pools on the coastal plain of Rio de Janeiro state in Brazil. These temporary blackwater habitats fill in the wet season and dry out later in the year.

Common questions

What size tank does a Constanciae killifish need?

A Constanciae killifish needs at least 11 gal (40 L). It spends most of its time in the middle.

What temperature and pH does a Constanciae killifish need?

A Constanciae killifish is comfortable at 68–77°F (20–25°C) with a pH of 5.5–7.0.

What does a Constanciae killifish eat?

A Constanciae killifish eats small live and frozen foods such as daphnia, brine shrimp, grindal worm and frozen bloodworm. These suit it far better than dry flake.

How big does a Constanciae killifish get?

An adult Constanciae killifish reaches about 2.4 in (6 cm).

How can you tell a male Constanciae killifish from a female?

Males carry the fins and pattern of a pearlfish.

How does a Constanciae killifish breed?

Constanciae killifish bury their eggs in a soft bottom. Spawn a pair over peat, then give the eggs a dry resting period before they hatch. Breeding them is moderately difficult.

Related species