1 kinds · tap one for a closer look
Peaceful upper-water shoaler.
The fish now sold as the penguin tetra is Thayeria boehlkei. T. obliqua is the blackline penguin tetra.
406 species in our list are a good match.
Peaceful upper-water shoaler.
Flakes, pellets.
Tap a food to see what it is.
Adult females are rounder in the belly and slightly less intensely coloured than males.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Egg-scatterer · Moderate
Egg scatterer; to raise fry, spawn in a separate tank because the adults eat the eggs.
Buy 6 or more and let them pair up.
20-40 L tank with fine plants or mops and soft water. Dim light.
Warm, soft water and good feeding.
A large spawn: usually around 1,000 eggs and up to 3,000. Eggs hatch in 12-24 hours and fry are free-swimming 3-4 days later.
Feed infusoria or green water for days 1-3, then newly hatched brine shrimp and microworms. Keep light low early on. Grow out in a larger tank once fish are about 1 cm.
Swims in an oblique, head-up posture, with a thick black stripe that runs from the gill cover along the body and down into the lower lobe of the tail, giving the trade name 'hockey-stick tetra'. Named after the ichthyologist James E. Böhlke.
American ichthyologist Stanley H. Weitzman described this tetra in 1957. The black stripe that runs into the lower tail lobe gives it a 'penguin' look. It usually swims at a head-up angle.
First described by Stanley H. Weitzman in 1957. Named for Named after ichthyologist James E. Böhlke.
16 facts checked with sources
Described by Weitzman, 1957. The common name 'penguin tetra' was first used for Thayeria obliqua; most fish sold as penguin tetras are T. boehlkei. Seriously Fish: in T. boehlkei the black stripe runs forward to the gill cover (opercle), while in T. obliqua it fades before the dorsal fin.
FishBase: Thayeria boehlkei summary · Seriously Fish: Thayeria boehlkeiFishBase places it in Acestrorhamphidae, subfamily Thayeriinae, following the 2024 split of Characidae (Melo et al. 2024). Seriously Fish (last revised 2012) still uses Characidae. FishBase preferred for taxonomy.
FishBase: Thayeria boehlkei summary · Wikipedia: Thayeria boehlkei · Seriously Fish: Thayeria boehlkeiLegacy 6 cm equals FishBase's reported maximum total length (TL). Typical standard length (SL, no tail) is 3.6 cm per both FishBase and Seriously Fish; 6 cm is a maximum, most fish stay smaller.
FishBase: Thayeria boehlkei summary · Seriously Fish: Thayeria boehlkeiLegacy range lies inside Seriously Fish's 5.5-8.0 (the quick-facts box says 'not recorded' but the water section gives this range). The site could widen the top to 8.0.
Seriously Fish: Thayeria boehlkei · FishBase: Thayeria boehlkei summaryNew value (legacy has none). Seriously Fish preferred for husbandry.
Seriously Fish: Thayeria boehlkei · FishBase: Thayeria boehlkei summary60 x 38 cm base x 30 cm height = 68.4 L; Seriously Fish lists ~68 litres. Legacy 80 L is more generous than the sourced minimum, not wrong in practice.
Seriously Fish: Thayeria boehlkeiNo source names a swimming level (legacy says top); FishBase only says pelagic.
FishBase: Thayeria boehlkei summarySeriously Fish's difficulty rating for maintenance is 'Easy'.
Seriously Fish: Thayeria boehlkeiNew value (legacy has no range).
Seriously Fish: Thayeria boehlkei · FishBase: Thayeria boehlkei summaryLegacy 50-200 eggs is far too low, and 24-36 h hatch is slower than both sources (Seriously Fish 12-24 h, FishBase 20-24 h).
Seriously Fish: Thayeria boehlkei · FishBase: Thayeria boehlkei summaryLegacy claims verified. Böhlke etymology from Wikipedia only.
Seriously Fish: Thayeria boehlkei · Wikipedia: Thayeria boehlkei