Species description

Care, breeding and tankmates

Fish profile

Temperament

Semi-aggressive

They are exceptionally timid and require heavy planting to feel safe. In a peaceful, dedicated micro-community, they are fascinating to watch. They are entirely non-aggressive and pose zero threat to any tank inhabitants.

Diet

Carnivore

They require tiny, specialized foods like infusoria and newly hatched brine shrimp. Finely powdered high-quality commercial flakes or micro-pellets are also accepted. A mature planted tank provides natural microfauna that supplements their diet perfectly.

Sex ratio

School

Keeping a large mixed group of ten or more creates a stunning natural display. Males are slightly more vibrant and will occasionally perform harmless lateral displays. A larger school gives them the confidence they need to explore the tank.

Feeding frequency

Twice daily

Frequent, tiny feedings two to three times a day are absolutely necessary. Their diminutive digestive systems process food quickly, so they cannot store much energy. Direct feeding using a pipette ensures they receive enough nourishment.

Bioload

The Least Pencilfish has an extremely low bioload, fitting for its micro-fish status. They produce barely any waste, making water quality easy to manage in mature tanks. A simple, low-flow sponge filter is entirely adequate for their needs.

Flow

Stagnant

They demand extremely gentle flow, mimicking their sluggish, weed-filled natural habitats. Strong currents will blow them around and cause severe, life-threatening stress. Gentle sponge filtration provides the necessary biological cleaning without excessive water movement.

Reproduction

Oviparous

Breeding is difficult due to the microscopic size of the fry, which require infusoria. They scatter their eggs among dense moss in soft, acidic water conditions. Adults will eat their own eggs and must be removed after spawning.

Compatibility & tankmates

They are completely peaceful and highly vulnerable to larger, active tank mates. They should only be housed with other micro-species or dwarf shrimp. Aggressive eaters will easily starve them by outcompeting them for food.

Tank level

Top/Middle

They generally hover in the upper and middle portions of the aquarium. They seek out calm pockets of water among dense plant leaves. They almost never venture to the substrate unless hunting for fallen morsels.