Penguin Tetra

Thayeria boehlkei

Animalia›Chordata›Actinopterygii›Characidae

📍 Amazon and Araguaia basins, Brazil

The penguin tetra is immediately recognised by its bold black stripe that runs down the lower body and into the lower caudal lobe — and by the unique way it holds its body at a nose-up angle while swimming. This head-up posture gives schools a distinctive, elegant appearance. A hardy, peaceful fish that suits most community setups.

Size2.5"

Min Tank20g

School6+

peaceful

Zonemid

Care Guide

Diet

Penguin tetras are omnivores that thrive on a varied diet of high-quality flake foods and micro pellets as staples. Supplement 2-3 times weekly with small frozen foods such as brine shrimp, daphnia, or bloodworms to promote color and condition. Feed small amounts once daily, only what they can consume in 2-3 minutes.

Behavior

Penguin tetras are peaceful, active schooling fish that display their characteristic nose-up swimming posture, creating an elegant visual effect in groups. They are mid-water swimmers that spend most of their time in the open, making them excellent community fish. Schools of 8+ individuals exhibit more natural behavior and reduced stress compared to smaller groups.

Breeding

Breeding penguin tetras in captivity is possible but moderately challenging and rarely achieved by hobbyists. They require soft, acidic water (pH 5.5–6.5), temperatures around 26–27°C, and dense vegetation or spawning mops for egg adhesion. Eggs hatch in 24–36 hours, and fry are extremely small, requiring infusoria or liquid fry food initially.

Tank Mates

Neon Tetra

Similar size, water requirements, and peaceful temperament; excellent community fish

excellent

Cardinal Tetra

Comparable size and habitat needs; both thrive in soft, slightly acidic water

excellent

Otocinclus

Small, peaceful algae eaters that won't compete with tetras and prefer similar conditions

good

Red Cherry Shrimp

Peaceful invertebrates that occupy different niches; ensure adequate vegetation for shrimp safety

good

Dwarf Gourami

Peaceful, slow-moving fish that won't outcompete tetras; compatible water parameters

good

Common Diseases

Ich (Ichthyophthirius multifiliis)

Symptoms

White spots on body and fins, rapid breathing, flashing against objects, lethargy

Treatment

Raise temperature gradually to 28–29°C, perform daily 25% water changes, use aquarium salt (1 tsp per 5 gallons) or commercial ich treatment; maintain for 10–14 days

Fin Rot

Symptoms

Frayed or deteriorating fins, discoloration at fin edges, fin loss

Treatment

Improve water quality with frequent partial water changes, reduce stocking density, treat with antibacterial medication if severe; ensure good filtration and remove decaying food

Neon Tetra Disease

Symptoms

Loss of coloration, spinal curvature, lethargy, erratic swimming behavior

Treatment

No cure exists; isolate affected fish to prevent spread, maintain pristine water conditions, and consider euthanasia if condition worsens; focus on prevention through quarantine and good husbandry

Columnaris (Flexibacter columnaris)

Symptoms

White or grayish film on body, mouth rot, fin deterioration, gasping at surface

Treatment

Perform large water changes, increase aeration, treat with antibacterial medication or salt baths; maintain temperature at 26–27°C and ensure excellent water quality