Introduction

Buying a Discus should never be based solely on its colour or price. A beautiful fish may hide underlying health issues, while a young Discus with less developed colours can grow into a stunning adult.

Before purchasing a Discus, it is essential to assess several key factors, including its behaviour, body shape, breathing, feeding response, and the conditions in which it has been raised.

In this guide, you'll learn the most important points to check before buying a Discus, helping you choose a healthy fish and maximise the chances of a successful acclimation.

Observe the Discus' Behaviour

Behaviour is often the first indicator of a Discus' overall health.

A healthy Discus should:

• Swim calmly throughout the aquarium.
• Remain curious when someone approaches the tank.
• Avoid hiding constantly.
• Display smooth and coordinated movements.

On the other hand, a Discus that remains isolated, stays motionless in a corner, or breathes rapidly deserves closer attention.

Check the Breathing

Normal breathing should be calm, regular, and barely noticeable.

Both gill covers (opercula) should move symmetrically.

Widely flared gills, rapid breathing, or only one gill cover moving may indicate gill disease or a parasitic infection.

Examine the Body Shape

A quality Discus should have:

• A round, symmetrical body shape.
• Well-balanced proportions.
• A smooth, rounded forehead.
• A slightly rounded belly without swelling.
• No visible deformities.

Avoid fish showing:

• An overly elongated body.
• A disproportionately large head.
• A sunken belly.
• A curved or deformed spine.

Look at the Eyes

The eyes should be:

• Clear and bright.
• Proportional to the size of the fish.
• Free from any cloudy appearance.

In young Discus, unusually large eyes compared to the body may indicate stunted growth.

Inspect the Fins

The fins should be:

• Fully extended.
• Complete and undamaged.
• Free from tears or fraying.
• Free from white spots.
• Without pale or whitish patches.

Fins that remain tightly clamped against the body may indicate stress or illness.

Evaluate the Colouration

Contrary to popular belief, a dark-coloured Discus is not necessarily unhealthy.

However, a very dark fish that also hides constantly, appears thin, or breathes heavily should raise concerns.

A Discus' colour naturally varies depending on:

• Age.
• Strain or variety.
• Diet.
• Lighting.
• Stress levels.

Observe the Feeding Response

Whenever possible, ask to watch the fish being fed.

A healthy Discus will usually swim confidently towards food and eat eagerly.

A fish that consistently refuses food or repeatedly spits it out should be observed more carefully before purchase.

Consider Its Origin

Not all Discus are bred under the same conditions.

Before buying, ask about:

• The country of origin.
• Breeding conditions.
• The diet used.
• Any previous treatments.
• The water conditions in which the fish has been raised.

A Discus already accustomed to water parameters similar to those in your aquarium will usually adapt more easily.

Don't Choose Based on Price Alone

A Discus sold at a very low price may require expensive treatments later or may have experienced poor growth.

Conversely, a fish raised in excellent conditions, properly fed, and well acclimated is often a safer long-term investment.

The Most Common Mistakes

• Choosing the cheapest fish available.
• Failing to observe its behaviour.
• Buying a Discus that is too small for your level of experience.
• Mixing Discus from different sources without a proper quarantine period.
• Forgetting to ask what food the fish has been eating.

Conclusion

Choosing a healthy Discus only takes a few minutes of careful observation, but it can prevent many problems in the future.

Take the time to assess its behaviour, breathing, body shape, appetite, and breeding environment. A carefully selected Discus will acclimate more easily and can thrive in your aquarium for many years.

Article written by Franck Le Bozec – Discus Breeder in Brittany, France

Founder of LB Discus, a French breeding facility specialising in the reproduction and sale of high-quality, French-bred Discus fish.