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Hemigrammus armstrongi

Hemigrammus armstrongi - Tetra Fish for Sale UK

Moderate Care
Peaceful
£3.99/ fishSold Out
Shoal Pricing
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Shoaling fish: kept in a group they feel safer, stay calmer and show their best colour.

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A peaceful, slender schooling tetra that thrives in soft, slightly acidic water and looks best in a lively shoal. Moderate care, peaceful. 23-26C, pH 5.5-7.0.

Care at a Glance

Scientific Name
Hemigrammus armstrongi
Max Adult Size
up to 5.3 cm
Lifespan
5 years
Care Level
Moderate
Temperament
Peaceful
Temperature
23–26°C
pH Range
5.5–7
Minimum Tank
40L
Diet
Omnivore

Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller. Product-photo provenance and any image-specific limitations are stated on the listing.

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Water Parameters

Maintain these water conditions for optimal health and vibrant colors

Temperature
23–26°C
23°CIdeal26°C
pH Level
5.5–7
5.5Ideal7

Introduction to the Hemigrammus armstrongi 1,

The Hemigrammus armstrongi 1, (Hemigrammus armstrongi) is peaceful, slender schooling tetra that thrives in soft, slightly acidic water and looks best in a lively shoal.

Whether you're an experienced aquarist or just starting your fishkeeping journey, the Hemigrammus armstrongi 1, offers a rewarding addition to a well-maintained community aquarium. Available for sale in the UK through Tropical Fish Co, this species combines ease of care with genuine character.

Species Fact: The genus Hemigrammus includes many popular aquarium species throughout South America.

Appearance and Colouration

The Hemigrammus armstrongi 1, typically reaches an adult size of around 1.5 cm, making it well-suited to medium-sized community aquariums. The species displays subtle but attractive natural colouration, which becomes more vibrant when maintained in optimal conditions.

Sexual dimorphism may be subtle in this species, though mature females are often slightly fuller-bodied when in breeding condition. Best colours are achieved through a varied diet, stable water chemistry, and the security of a proper shoal.

Origins and Wild Habitat

In the wild, Hemigrammus armstrongi is found in South America; exact wild range is not well documented in aquarium sources, but the genus is native to Amazon basin tributaries. These fish typically inhabit slow-moving tributaries, forest streams, and floodplain pools where water is soft, warm, and often stained with tannins from decaying organic matter.

The natural environment of the Hemigrammus armstrongi 1, features dense aquatic vegetation, submerged roots, and leaf litter, creating a complex habitat with dappled light and plenty of hiding spaces. Replicating these conditions in the home aquarium helps reduce stress and encourages natural behaviour.

Aquarium Setup and Tank Requirements

A minimum aquarium volume of 40 litres is recommended for a small group of Hemigrammus armstrongi 1,. Provide a well-planted layout with open swimming areas, subdued lighting, and a dark substrate to help the fish feel secure and display their best colours.

Include plenty of live plants (such as Java Fern, Anubias, or Amazon Sword), driftwood, and smooth rocks to create a naturalistic environment. Efficient filtration is essential, but avoid strong currents; gentle water movement mimics the calm waters these fish prefer in the wild.

A secure aquarium lid is important, as many small characins are capable jumpers when startled. Regular partial water changes and stable conditions are key to long-term health and vitality.

Maintaining Water Chemistry

The Hemigrammus armstrongi 1, thrives in water temperatures between 23-26C, with a pH range of 5.5-7.0. Soft to moderately soft water is preferred, and the addition of natural tannins (via catappa leaves or driftwood) can help replicate wild conditions and support overall health.

Maintain excellent water quality through regular testing and partial water changes (20-30% weekly is a good guideline). Ammonia and nitrite should always be zero, and nitrate levels kept low through diligent aquarium maintenance and efficient biological filtration.

Avoid sudden fluctuations in temperature or chemistry, as stability is more important than hitting exact parameter targets. Acclimatise new fish slowly using the drip method to minimise stress and reduce the risk of shock.

Expert Advice: Always acclimatise new Hemigrammus armstrongi 1, slowly using the drip method to avoid temperature and chemistry shock.

Nutritional Needs and Feeding Schedule

As an omnivore, the Hemigrammus armstrongi 1, requires a varied and balanced diet to maintain vibrant colours and robust health. Offer a varied diet of high-quality flake or micro-pellets supplemented with frozen and live foods such as daphnia, brine shrimp, and bloodworms; small meaty foods help maintain color and condition.

Feed small portions two to three times daily, offering only what can be consumed within a few minutes to prevent water quality degradation. A varied diet not only enhances colour and condition but also supports the immune system and encourages natural foraging behaviour.

High-quality commercial foods formulated for small tropical fish provide a solid foundation, but regular supplementation with live or frozen foods will bring out the best in this species.

Behaviour and Social Structure

The Hemigrammus armstrongi 1, is a peaceful species that does best when kept in a group of six or more individuals. Shoaling behaviour is natural and essential for their confidence; solitary specimens or those kept in insufficient numbers may become timid, stressed, or occasionally nippy.

These fish are active swimmers that occupy the mid to upper levels of the aquarium, where they forage, explore, and interact with their shoal-mates. Their natural behaviour is most evident in a well-planted tank with gentle lighting and calm water flow.

Observing a healthy shoal of Hemigrammus armstrongi 1, is a genuine pleasure, as they move together in fluid formations and respond to environmental cues with natural grace.

Choosing Suitable Tank Companions

The Hemigrammus armstrongi 1, is an excellent choice for a peaceful community aquarium. Suitable tank mates include Other peaceful small tetras, Rasboras, Corydoras catfish, and other similarly sized, non-aggressive species that share comparable water parameter requirements.

Avoid housing with Large predatory fish, Aggressive cichlids, Fin-nipping barbs, or any fish large or aggressive enough to intimidate or prey upon this species. Peaceful invertebrates such as small shrimp and snails can also coexist safely, though very small shrimp fry may occasionally be eaten.

Always research the specific needs and temperament of any prospective tank mates before introduction, and ensure the aquarium is large enough to accommodate all inhabitants comfortably.

Spawning Behaviour and Fry Care

Breeding the Hemigrammus armstrongi 1, in the home aquarium is possible but may require specific conditions and careful preparation. Likely an egg-scattering tetra that spawns among fine-leaved plants or spawning mops in soft, acidic water; parents should be removed after spawning because eggs and fry are vulnerable to predation.

A separate breeding tank with soft, slightly acidic water and fine-leaved plants or spawning mops will encourage spawning. Condition prospective parents with high-quality live and frozen foods to bring them into peak breeding condition.

Fry are tiny and require very small live foods such as infusoria or commercial liquid fry food initially, graduating to freshly hatched brine shrimp as they grow. Patience, attention to water quality, and careful feeding are essential for success.

Quality Guarantee and Expert Support

At Tropical Fish Co, we specialise in supplying healthy, responsibly sourced Hemigrammus armstrongi 1, and a wide range of other freshwater tropical fish for sale in the UK. Every fish is carefully selected, quarantined, and conditioned before dispatch to ensure you receive livestock in peak condition.

Our expert team is on hand to provide tailored advice on aquarium setup, water chemistry, diet, and compatibility, whether you're establishing your first aquarium or expanding an existing collection.

We offer reliable UK-wide delivery, excellent customer service, and a commitment to quality that has made us a trusted name among hobbyists across the country. When you buy from Tropical Fish Co, you're investing in livestock backed by genuine expertise and care.

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What customers say about ordering from us

  • 4 out of 5Verified buyer

    I have a small group of long finned mountain minnows. So was delighted to be able to order ten of this variety to increase the genetics in my tank . The ones I recieved are healthy but it’s to early to give a verdict on wether they are of a long finned type since they are small currently.

    Gordon Walker · 23 Sept 2026

  • 5 out of 5Verified buyer

    100% success travel and "installation". Pleased with quality of purchase. The Siamese fighter a bit "shy" so have not yet seen him at his best yet but looking good. Happy customer. GG

    George E Garratt · 21 Sept 2026

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