Why do Penguinfish swim at an angle?

Their distinctive head-up swimming posture is natural behaviour, not a sign of illness. It gives them their common name, as they resemble penguins standing upright.

Are Blackline Penguinfish good for beginners?

Yes, they are hardy, easy to care for, and adapt well to a range of water conditions. They are peaceful and ideal for community tanks.

How many Penguinfish should I keep?

Keep at least 6, ideally 10 or more. Larger groups create a more impressive display and the fish feel more secure, showing better colouration.

How big do Blackline Penguinfish get?

Adults reach approximately 8 cm. They need a minimum tank of 80 litres for a proper school.

What temperature do Penguinfish need?

They prefer slightly cooler tropical temperatures of 22-26°C, which is lower than many tropical fish. This makes them compatible with a wide range of species.

Thayeria boehlkei

Penguin Tetra — Blackline Penguinfish (Thayeria boehlkei) - Pack of 10

Name: Penguin Tetra — Blackline Penguinfish (Thayeria boehlkei) - Pack of 10
Brand: Tropical Fish Co
SKU: 2432
Price: 1.99 GBP
Availability: PreOrder

Beginner Friendly

Peaceful

£1.99In Stock

A unique schooling tetra that swims at a distinctive head-up angle with a bold black line. Hardy and peaceful, ideal for community tanks. Pack of 10 with live arrival guarantee.

CharacidaeEasy CareLive FishPeacefulSchooling Fishsite:tropical-fish-coSouth American TetraTetra

Care at a Glance

Scientific Name

Thayeria boehlkei

Adult Size

8 cm

Lifespan

5 years

Care Level

Easy

Temperament

Peaceful

Temperature

22–26°C

pH Range

6–7.5

Hardness

5–15 dGH

Minimum Tank

80L

Diet

Flakes, micro pellets, small live foods

Water Parameters

Maintain these water conditions for optimal health and vibrant colors

Temperature

22–26°C

22°CIdeal Range26°C

pH Level

6–7.5

6Ideal Range7.5

Water Hardness

5–15 dGH

5 dGHIdeal Range15 dGH

The Blackline Penguinfish (Thayeria boehlkei), also known as the Penguin Tetra, is a unique schooling fish named for its distinctive head-up swimming posture. Originating from the Amazon basin in Brazil, this peaceful species is rated as easy care and can live up to 5 years.

Care at a Glance

Scientific Name	Thayeria boehlkei
Family	Characidae
Origin	South America (Brazil, Amazon)
Care Level	Easy
Temperament	Peaceful
Adult Size	8 cm
Minimum Tank Size	80 litres
Temperature	22–26°C
pH Range	6.0–7.5
Water Hardness	5–15 dGH
Diet	Flakes, micro pellets, small live foods
Lifespan	5 years
Tank Region	Middle
Group Size	6+ (schooling)

Origin & Natural Habitat

The Blackline Penguinfish is endemic to the Amazon River basin and Araguaia River in Peru and Brazil. In the wild, they inhabit slow-moving waters among vegetation. Their distinctive angled swimming posture and bold black stripe make them instantly recognisable.

Tank Setup & Water Parameters

Provide a minimum of 80 litres with gentle filtration and well-oxygenated water. Adults reach approximately 8 cm. Maintain water temperature between 22–26°C with a pH of 6.0–7.5 and hardness of 5–15 dGH. They appreciate some water flow.

Feeding Guide

The Blackline Penguinfish is an omnivore. Offer quality flakes, micro pellets, and small live or frozen foods such as daphnia and brine shrimp. They are unfussy eaters. Feed small amounts twice daily.

Compatible Tank Mates

Good companions include other tetras, corydoras, rasboras, and dwarf cichlids. Avoid large aggressive fish. You might also consider species such as Royal Tetras, Red Phantom Tetras, and Red Golden Pencilfish from our collection.

Why Buy from Tropical Fish Co?

At Tropical Fish Co, every fish is carefully selected and shipped with care across the UK. We offer live arrival guarantee, expert advice, and competitive prices. Order your Blackline Penguinfish today and enjoy next-day delivery to your door.

Licensed Courier

Moved by UK carriers licensed to handle live animals

Trained Packing

Hand-packed with oxygen bags, poly box, heat pack

Live Arrival Guarantee

Replacement or refund — just tell us the same day

Pay Later Available

Klarna & PayPal Pay in 3 at checkout

How your fish gets to you

Dispatched Tuesday, delivered Wednesday — every order tracked and insured.

Dispatched on Tuesdays by a UK courier legally licensed to carry live animals. You’ll get a tracking number on dispatch morning and live updates through the afternoon.
Hand-packed in an insulated poly box with oxygen bags and (Oct–Apr) 40-hour heat packs. £20 flat rate covers any number of fish.
Covered by our Live Arrival Guarantee. Tell us the same day your fish arrive with a short unboxing video — replacement or refund, no arguments. Why we need a video
You need to be home.Live fish cannot be left on doorsteps or with neighbours — it kills them. Please only order for days when someone will be in to sign.

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