Kribensis

Quick facts

Adult size

10 cm

Lifespan

can live up to 7 years; hardy and long-lived for a dwarf cichlid

Tank zone

bottom

Temperament

semi-aggressive

Difficulty

beginner

Water parameters

Temperature

24–28°C

pH

6.0 to 8.0

Hardness

5 to 20 dGH

Tank requirements

Minimum volume

110 L

Minimum length

75 cm

Flow

low

Lighting

dim preferred

Substrate

any

Driftwood

preferred

Hiding spots

needed

Feeding

Diet: omnivore, feeds primarily at the bottom.

Omnivore that eats flake food, pellets, frozen bloodworm, frozen brine shrimp, frozen daphnia, and live food. Not picky. Feeds at the bottom and in the midwater column. During breeding, both parents forage heavily to fuel egg production and fry guarding. A varied diet with frozen food 2-3 times weekly keeps coloring vibrant, especially the female's characteristic cherry-red belly. Feed twice daily.

Compatibility

• One of the more manageable dwarf cichlids for community tanks, but still a cichlid. A breeding pair defends a territory roughly 30 cm in radius around their cave and will chase anything that enters it, regardless of species or size.
• Outside of breeding, relatively peaceful. Pairs coexist with mid-water community fish (tetras, rasboras, barbs) without conflict, provided the community fish don't stray near the cave.
• Bottom-dwelling tankmates (corydoras, loaches) get the worst of it during breeding because they wander into the defended territory while foraging. This rarely causes injury but the constant chasing stresses them.
• A pair is the standard way to keep kribs. Single specimens are peaceful but lack the interesting behavior. Two pairs in the same tank need 200 L and two distinct cave sites on opposite ends.

Habitat

Native to coastal river drainages in Nigeria and Cameroon in West Africa. Found in slow-moving water with sandy substrates, submerged wood, and dense vegetation. The species has been the entry-level dwarf cichlid for decades because it's hardy, colorful, breeds readily, and stays small (10 cm for males, 7–8 cm for females). The male is larger with pointed dorsal and anal fins and more iridescent blue-green body color. The female is smaller but more colorful: a vivid cherry-red belly that intensifies during breeding, dark body bars, and gold tones. The sex of the fry is influenced by water pH during development, a trait shared with some other cichlids. Acidic water (pH below 7) produces more females; alkaline water (above 7) produces more males. Neutral pH yields a roughly even split. This has been documented in breeding studies and is one of the more reliably demonstrated cases of environmental sex determination in fish. Commercially bred stock is widely available and inexpensive.

Breeding

Cave spawner that breeds readily in aquariums. Provide a cave (coconut shell half, overturned clay pot, or driftwood cave) and a pair will usually spawn within weeks of being established. The female takes the lead in courtship, displaying her red belly and shimmying in front of the male near the cave entrance. She deposits 200-300 adhesive eggs on the cave ceiling. Both parents guard the eggs, but the female does most of the direct egg tending inside the cave while the male patrols the perimeter. Eggs hatch in 3-4 days. Fry are free-swimming in another 4-5 days. Both parents shepherd the fry around the tank in a tight cloud, aggressively repelling any fish that approaches. Watching krib parents manage their fry school is one of the best behavioral displays in the freshwater hobby. Fry eat baby brine shrimp and crushed flake from day one. The parents maintain guard duty for 3-4 weeks, after which the fry disperse and the pair may spawn again. Kribs are prolific; a healthy pair produces a brood every 6-8 weeks.

Common problems

Aggression during breeding catches community-tank keepers off guard. A pair that was peaceful for months suddenly becomes territorial the moment eggs are laid. The solution is a large enough tank (120 L) with enough mid-water space that other fish can stay out of the defended zone. Hexamita (hole-in-the-head disease) occurs occasionally, especially on low-quality diets. Symptoms: pits forming on the head and lateral line. Treat with metronidazole and improve the diet. Females sometimes become egg-bound (unable to release eggs), showing as a swollen abdomen and lethargy. A large water change with slightly cooler water can trigger egg release. The pH-sex-determination effect means that breeders in very soft or very hard water end up with skewed sex ratios, which is frustrating when you want balanced breeding groups. If all your krib fry are females, raise the pH slightly for the next brood.

Bioload

Bioload coefficient: 2.8 (moderate-sized active cichlid; comparable per-cm to common platy or larger livebearer).

Bioload coefficients are calibrated against the neon tetra as the anchor (1.0). See the methodology page for the formula and how each value was derived.

Further reading

• How to cycle a fish tank
• Stocking ideas by tank size