Betta Fish Care in the UK: Beginner Guide, Tank Size, Heating & Costs

Betta fish are one of the most popular freshwater fish in the UK, especially among first-time aquarium keepers. Their striking colours, individual personalities, and ability to live alone make them appealing, particularly for people with limited space.

However, bettas are also one of the most misunderstood fish species. Many problems in UK homes come from small 10-litre tanks, unstable temperatures, and unrealistic expectations about how “easy” they are to keep.

This guide explains exactly how to care for betta fish properly in the UK, where smaller homes, cooler indoor temperatures, and beginner misinformation often lead to common mistakes

Quick answer

In the UK, a betta fish should be kept alone in a heated and filtered aquarium of at least 20–30 litres. While bettas are hardy, long-term success depends on stable temperature (24–27°C), adequate tank size, and consistent water quality rather than minimal equipment.

This Guide Covers:

• Betta fish care in typical UK homes
• Recommended tank size for long-term health
• Heating, filtration, and oxygen requirements
• Behaviour, temperament, and compatibility
• Betta fish UK price and realistic ongoing costs
• Common beginner mistakes and how to avoid them
  

Quick Navigation:

• Are Betta Fish Good for Beginners?
• What Makes Betta Fish Popular in the UK?
• Is It Better to Have 1 or 2 Betta Fish?
• How Big a Tank Should be for 1 Betta Fish?
• Do Betta Fish Need a Heater in the UK?
• Does a Betta Fish Need an Oxygen or Air Pump?
• Betta Fish Water Conditions in the UK
• Feeding Betta Fish Correctly
• Betta Fish Behaviour and Tank Mates
• Betta Fish Varieties Commonly Sold in the UK
• How Expensive Is a Betta Fish?
• Common Betta Fish Mistakes to Avoid
• Frequently Asked Questions
• Final Thoughts

Are Betta Fish Good for Beginners?

Betta fish can be a good choice for beginners in the UK if their real needs are understood and respected.

They are hardy compared to many tropical species, do not require tank mates, and tolerate gentle filtration. However, they are not low-maintenance fish and struggle when kept in very small, unheated tanks.

Bettas suit beginners who:

• are willing to use a heater
• can provide stable water conditions
• understand that “small fish” does not mean “small effort”

What Makes Betta Fish Popular in the UK?

Betta fish, also known as Siamese fighting fish, are popular in the UK for several reasons:

• They can be kept alone, without a community tank
• They are visually striking, even in smaller aquariums
• They tolerate calm water flow
• They are widely available in UK aquatic shops

These traits make bettas appealing for flats, smaller homes, and beginners. However, popularity does not automatically mean they are low-maintenance or suitable for very small tanks.

Is It Better to Have 1 or 2 Betta Fish?

For most aquariums, one betta fish is always the better choice.

Male bettas are highly territorial and should never be kept together. If housed together, they will fight, often leading to serious injury or death. Even two males separated by glass can become stressed by constant visual contact. 

Most betta fish sold in the UK are males. Female bettas have the same basic care requirements, tank size, heater, and filtration, but display different social behaviour and should not be considered “easier” for beginners.

Female bettas are sometimes kept in groups (called sororities), but this requires:

• large tanks (usually 100 litres or more)
• careful stocking
• experience with betta behaviour

For beginners in the UK, a single betta fish kept alone is the safest and most responsible option. Keeping multiple bettas requires experience, larger tanks, and careful planning and is not recommended for beginners. 

How Big a Tank Should be for 1 Betta Fish?

When considering betta fish tank size in the UK, water volume matters far more than the fish’s small physical size.

A single betta fish should be kept in a tank of at least 20 litres in the UK. While bettas are often marketed as suitable for small aquariums, tanks under 20 litres are unstable and more affected by temperature and water quality fluctuations common in UK homes. 

Understanding how tank size impacts a betta’s environment helps avoid many of the common problems seen in first-time setups.

Betta Tank Sizes Comparison

In UK homes, especially during winter, small tanks cool quickly. A 20–30 litre aquarium provides better thermal stability and reduces maintenance demands. 

In practical terms, tank volume influences how stable the environment remains day to day, especially in smaller UK homes.

Recommended Betta Fish Setup (UK Reality)

The table below reflects realistic requirements for betta fish in UK homes, focusing on stability rather than minimum survival conditions.

Beyond volume, bettas benefit from a thoughtfully arranged tank with live or silk plants, gentle hiding areas, and calm surface access for breathing. A well-structured layout reduces stress and encourages natural behaviour, especially in smaller aquariums.

Do Betta Fish Need a Heater in the UK?

Yes. In the UK, indoor temperatures fluctuate far more than many beginners realise.

Betta fish are tropical and require stable water temperatures between 24°C and 27°C in the UK. Most UK homes do not maintain this temperature consistently, especially overnight and during winter months, making a reliable aquarium heater essential for betta health and long-term wellbeing.

Without a heater:

• immune systems weaken
• stress increases
• illness becomes more likely

Most UK homes do not maintain temperatures consistently, especially overnight, as shown by typical indoor temperatures in UK homes. A small, reliable aquarium heater is one of the most important pieces of equipment for betta care.

Does a Betta Fish Need an Oxygen or Air Pump?

Betta fish do not require an air pump to breathe because they have a labyrinth organ that allows them to take oxygen directly from the surface. However, this does NOT mean they can live in poor water conditions.

However, gentle filtration is still necessary to:

• prevent waste buildup
• surface agitation from a filter outlet
• clean, oxygenated water

An air pump can be useful in heavily planted tanks or during hot weather, but it is not essential for most UK setups.

Betta Fish Water Conditions in the UK

Water conditions are one of the most common sources of confusion for betta fish keepers in the UK. Most betta health issues are caused by unstable conditions rather than unsuitable tap water.

Understanding how UK tap water behaves in an aquarium helps beginners avoid unnecessary adjustments and long-term problems.

Is UK tap water safe for betta fish?

Yes, it is generally safe for betta fish once treated with a water conditioner to remove chlorine and chloramine in UK tap water. In most parts of the UK, tap water is suitable as long as it is dechlorinated and kept stable over time.

Key points:

• Dechlorinate all new water
• Avoid chasing exact pH numbers
• Stability matters more than perfection

Even when tap water is properly treated, water stability depends heavily on whether the aquarium has been correctly cycled before fish are added.

Why tank cycling matters

Bettas are often added to uncycled tanks, which leads to ammonia spikes and illness. Understanding how aquarium cycling works establishes beneficial bacteria that process waste safely and prevents early losses in new aquariums.

A cycled tank:

• reduces stress
• prevents sudden losses
• makes maintenance easier

Feeding Betta Fish Correctly

Feeding is one of the most underestimated aspects of betta fish care. While bettas are enthusiastic eaters, incorrect feeding routines are a common cause of health issues in beginner aquariums. Understanding how much and how often to feed helps maintain both fish health and water quality over time.

How often should you feed a betta fish?

• Small amounts, once or twice daily (morning and evening if fed twice daily)
• Offer 2–4 small pellets per feeding, adjusting based on fish size
• Only feed what is fully eaten within 1–2 minutes
• One fasting day per week can help digestion

Most adult betta fish only need 2–4 small betta pellets per feeding, depending on their size and activity level.

Small pellets refer to the tiny granules specifically labelled for betta fish, usually around 1 mm in size. These are different from standard tropical fish pellets, which are often too large and dense for bettas.

Overfeeding quickly leads to bloating and poor water quality in small aquariums. 

Betta Fish Behaviour and Tank Mates

Betta fish behaviour is often misunderstood due to their reputation as “aggressive” fish. In reality, their temperament is closely linked to territory, tank size, and environmental stress. Understanding how bettas interact with their surroundings is essential before considering any tank mates.

Can betta fish live with other fish?

Sometimes, but only under the right conditions.

Possible tank mates (with caution):

• snails
• shrimp (may be eaten)
• very calm, non-fin-nipping species in larger tanks

Never keep bettas with:

• other bettas
• aggressive fish
• fast fin-nippers

For most beginners, a single-species betta tank is the safest option.

Betta Fish Varieties Commonly Sold in the UK

Betta fish sold in the UK come in a wide range of selectively bred varieties. While these fish share the same basic care requirements, some varieties are more delicate due to their body shape or fin size.

Understanding these differences helps beginners choose a betta that is easier to care for and less prone to stress or injury.

Double Tail Betta

• Shorter body
• Larger fins
• Often, less strong swimmers

Halfmoon Betta

• very large fins
• visually striking
• more prone to fin damage

Fancy betta varieties often require cleaner water, gentler filtration, and closer observation. In UK aquatic shops, you may also see names such as double tail halfmoon betta, halfmoon double tail betta, "king betta", or moon tail betta. These are marketing terms describing fin shape, size, or colour patterns, rather than different species and often come with higher care demands due to their large, delicate fins.

While they can thrive in the right setup, they are generally less forgiving of mistakes, making them better suited to stable, well-maintained aquariums.

How Expensive Is a Betta Fish?

In the UK, betta fish typically cost between £10 and £30, depending on colour, tail type, and overall quality. Selectively bred or rare varieties can cost significantly more.

• Standard betta: £10–£25
• Fancy or rare strains: £30–£80+

However, the fish itself is only a small part of the overall cost. Proper housing, heating, filtration, and ongoing maintenance usually cost more than the betta fish itself.

Typical beginner setup costs in the UK include:

• Aquarium & stand: £40–£100+
• Filter & heater: £30–£80
• Food & conditioner: £5–£15 monthly

These ranges reflect typical UK online prices for entry-level to mid-range equipment at the time of writing and can vary depending on brand, tank size, and personal preferences.

Common Betta Fish Mistakes to Avoid

Many betta problems come from misinformation rather than the fish itself.

The most common mistakes include:

• keeping bettas in unheated tanks
• using tanks under 10 litres
• strong filtration or high flow
• skipping cycling before adding fish
• skipping a heater
• overfeeding
• assuming bettas are “easy” or disposable fish

These issues often lead to stress, disease, and shortened lifespan. 

How long do betta fish live?

In UK home aquariums, betta fish typically live between 3 and 5 years when kept in stable, heated tanks with good water quality. Lifespan is strongly influenced by tank size, temperature stability, and regular maintenance rather than genetics alone.

Frequently Asked Questions

Are betta fish good for beginners in the UK?

Yes, if kept alone in a heated, filtered tank of adequate size and maintained properly. 

Can betta fish live in a 10L tank?

They can survive, but it is not ideal. Tanks under 20 litres are unstable and require frequent maintenance. Larger tanks are healthier and easier to manage.

How long can betta fish live with proper care?

Typically, 3–5 years with good care and stable conditions.

Can a betta fish live without a filter?

Short-term survival is possible, but filtration greatly improves water quality and stability.

Do betta fish recognise their owners?

Many bettas show curiosity and recognise feeding routines, often appearing interactive compared to other fish. 

Can beginners keep betta fish successfully?

Yes, provided they use a heater, an appropriate tank size, and understand basic aquarium care.

Are betta fish legal to sell in the UK?

Yes, betta fish are legal and widely sold by UK aquatic retailers.

Final Thoughts

Betta fish can be rewarding, intelligent fish when their real needs are understood. While they are often marketed as simple beginner fish, they thrive best in heated, stable aquariums with enough space to swim and explore.

A thoughtful setup, patience during cycling, and realistic expectations lead to healthier fish and a far more enjoyable experience. 

If you’re planning your first aquarium or refining an existing setup, understanding the basics of choosing the right aquarium for your home and taking the time to build stability before adding life will make every future decision easier.

Guide written by the AquaticsHub team – UK-based aquarists.