Betta Fish Care Guide: Betta splendens for UK Aquarists

The betta fish (Betta splendens) is the species I get asked about more than any other — by beginners wondering if it is true they can live in a cup, by people who lost one in a bowl and want to do better next time, and by experienced keepers trying to work out why their community tank suddenly turned hostile. This guide is the answer I give all of them, written from 15 years of keeping bettas in UK conditions and based on every honest observation I can offer.

This guide draws on data from FishBase^[1] and Seriously Fish^[2], cross-referenced with years of keeping this species in UK tap water. Every care parameter here is sourced, and where I give an opinion I will tell you it is one.

We currently stock a range of betta fish — browse our betta collection to see what is available for tracked UK delivery.

The bowl myth — and why it refuses to die

No other fish in the hobby has been as consistently mis-sold as the betta. Plastic cups on shop shelves, unheated vases marketed as "betta kits", desktop ornaments the size of a coffee mug — every one of these displays sells the idea that bettas can live in tiny, unheated, unfiltered water. They cannot.

The myth survives because wild bettas are sometimes found in shallow rice paddies and road-side puddles during the dry season. What gets left out is that those puddles are connected to vast seasonal floodplains, are often over 26 degrees Celsius, and the fish move on at the first rain. A puddle is not where bettas live happily — it is where they survive temporarily.

A minimum of 20 litres, a heater, and a gentle filter turn a "difficult" fish into one of the easiest tropicals you can keep. This guide assumes you are going to do it properly.

Where bettas come from

Betta splendens is native to Thailand, Cambodia, Vietnam, and parts of Laos, inhabiting the Mekong basin and surrounding slow-moving, heavily vegetated waters^[1]. Rice paddies, flooded fields, shallow ponds, and slow oxbow streams are all typical habitat — warm, shaded, often low in dissolved oxygen, and densely planted with marginal vegetation^[2].

Two things make sense of betta biology once you know them. First, this habitat is warm year-round — water temperatures sit in the mid-20s Celsius, and that is where the fish's metabolism is tuned. Second, the shallow, oxygen-poor conditions drove the evolution of the labyrinth organ, a specialised structure above the gills that lets the betta breathe atmospheric air directly from the surface^[1].

The labyrinth organ explains two practical points: bettas must have access to the surface (a sealed-lid setup will kill them), and they tolerate lower dissolved oxygen than most tropical fish, which is why they survive in tanks with gentle filtration. It does not mean they prefer stagnant water or need no filtration at all.

Almost every betta sold today is captive-bred. Commercial strains have been selectively bred for colour and fin shape for over a century, with the major production centres in Thailand and Indonesia. Wild-type Betta splendens are short-finned, drab, and aggressive — beautiful in their own way but very different from the flowing show strains most people picture.

Tank setup

Size and layout

Twenty litres is the minimum I will ever recommend — and I mean a proper 20-litre tank, not a 20-litre bowl. Thirty to forty litres is a much better starting point. The larger volume is easier to heat stably, easier to keep clean between water changes, and gives the fish room to move naturally rather than sulking in one corner.

Horizontal footprint matters far more than height. Bettas are shallow-water fish — in the wild they cruise under surface vegetation, not up and down water columns. A wide, low tank of 35 by 25 cm will keep a betta happier than a tall 20-litre pillar tank every time.

Stocking suggestions

Lid and air gap — critical

This one catches people out. Bettas jump — they are surface feeders with a labyrinth organ, and they will absolutely launch themselves at anything they mistake for a gnat. A tight-fitting lid is essential. Tanks with cut-outs for cables should be sealed with sponge or mesh.

Equally important, you need a 2-3 cm air gap between the water surface and the lid. The betta needs to breathe air at the surface, and the air in that gap should be warm and humid. A cold draft on the labyrinth organ can cause damage. Opening the lid in a chilly UK kitchen during winter without warming the room first is a common low-level stressor.

Water parameters

The standard range is 24-28 degrees C^[1], with most captive-bred fish doing best around 26 degrees. Below 24, metabolism slows and the immune system weakens; above 28, the fish ages faster and oxygen carrying capacity drops. A reliable thermostatic heater is non-negotiable.

pH should sit between 6.5 and 7.5, with most tap-water tanks in the UK landing naturally in that range^[2]. Hardness is flexible — 3 to 15 dGH is well within what bettas tolerate. They are not soft-water specialists like wild discus or neon tetras.

Filtration

Gentle flow is the rule. A small sponge filter running off an air pump is perfect for a 20-40 litre betta tank — it provides biological filtration without producing current that beats up heavy fins. For larger planted tanks, an internal or hang-on-back filter with a baffled outlet works, as long as you can reduce the flow enough that floating leaves drift slowly rather than race.

If your betta sits in the current trying to hold position, the flow is too strong. If he has to work to reach the surface, the flow is too strong. A happy betta cruises calmly, rests on leaves, and makes deliberate trips to the surface without effort.

Substrate and decor

Dark sand or fine dark gravel brings out the colour beautifully. Aquasoil works too if you are running a planted setup. Avoid any substrate with sharp edges — cheap coloured gravel with broken corners will scratch a fish that likes to rest on the bottom.

For decor, the golden rule is no sharp edges. Heavy-finned show strain bettas will catch and tear their fins on jagged plastic plants, rough rock, or anything with a spiky silhouette. Silk plants are safer than plastic. Live plants are safest of all. Broad-leaved species like Anubias, Cryptocoryne wendtii, and Echinodorus give resting spots near the surface, which bettas love.

Floating plants are brilliant. They shade the tank, provide anchor points for bubble nests, and make the betta feel secure under cover. Amazon frogbit, salvinia, and red root floater all work. Indian almond leaves (catappa) add tannins that tint the water lightly and have mild antibacterial properties — a handful of keepers swear by them, and they cannot hurt.

Lighting

Moderate to low is ideal. Bright overhead lighting with no plant cover stresses them and bleaches their colour under long exposure. Lighting filtered through floating plants produces the dappled look bettas have evolved under, and it brings out the iridescence of scales and fins. I run 7-8 hours a day on any planted betta setup.

Feeding

Bettas are carnivores. Not omnivores — carnivores. In the wild they eat insects, larvae, and small invertebrates almost exclusively, and their digestive system is short and protein-focused^[2]. A diet built around flake food made for general community tanks will leave them undernourished and prone to gut issues.

Daily staple

A quality betta-specific pellet is the best everyday food. Look for the first ingredient to be a named protein source — whole fish, shrimp meal, or black soldier fly larvae — not wheat or starch filler. Feed 2-3 pellets once or twice a day. That is all. Bettas have a stomach roughly the size of their eye, and overfeeding is the single most common mistake I see.

Supplementary foods

Two or three times a week, offer frozen bloodworm, brine shrimp, daphnia, or mysis. These build muscle, improve colour, and give the fish something to hunt. Thaw frozen cubes in a small cup of tank water first — never drop a rock-solid cube of bloodworm into the tank, where it hits the substrate and fouls the water as it thaws.

Live foods are a treat if you can source them. Live daphnia, mosquito larvae (outdoor bug hotel in summer), or blackworms all produce visible benefit. They also help with constipation, which bettas are prone to on an all-pellet diet.

The weekly fast

One fasting day a week is genuinely good for bettas. Their digestion benefits from the break, and it reduces the risk of bloating, constipation, and swim bladder issues. I pick a day that suits my week and skip the feed — the fish does not suffer, and by morning it will be alert and keen for the next meal.

Avoid

Generic tropical flakes as a main diet — wrong protein profile, and many bettas refuse them anyway. Large pellets that cannot fit the fish's mouth. Any food left uneaten for more than a few minutes: scoop it out, because it is going to rot and spike ammonia in a small tank.

Appearance and varieties

Wild-type Betta splendens is a modestly-coloured, short-finned fish around 6-7 cm in length^[1]. Everything else you see in the hobby — the flowing veiltails, the iridescent halfmoons, the marbled koi — is the result of generations of selective breeding for fin shape and colour.

Tail and fin types

• Veiltail — the classic pet-shop betta. Long, asymmetrical tail that drapes downward. Still the most common variety.
• Halfmoon — tail spreads to a full 180-degree arc when flared. Show-quality fish can look extraordinary, but heavy fins stress the swim muscles.
• Crowntail — spiky, rayed fins with webbing reduced between the rays. Dramatic look, but prone to ray curling if water quality slips.
• Plakat — short-finned, closer to the wild form. The healthiest and most active variety; many experienced keepers prefer them.
• Double tail — tail split into two distinct lobes. Often paired with deeper bodies.
• Dumbo / elephant ear — enlarged pectoral fins. Adorable but vulnerable to tears.
• Delta and super delta — less extreme than halfmoon, a symmetrical tail between veil and halfmoon.

Colour varieties

There are more named betta colour strains than any sensible guide could list. The common ones include solid reds, blues, and blacks; bicolours; marble patterns; koi (white with red and black splashes); galaxy (iridescent speckling); mustard gas (dark body, yellow fins); and dragon scale (thick iridescent scales over a coloured body).

My practical advice after years of keeping these: plakats and shorter-finned varieties live longer, active lives. The extreme halfmoon and dumbo strains are beautiful but carry real welfare costs — swim issues, fin damage, shorter lifespans. If you are new to bettas, a wild-type or plakat is a better fish than an extreme show strain.

Male vs female

Males have the long fins and bold colour people associate with bettas. Females are shorter-finned, slightly smaller, often duller, and show vertical breeding bars when ready to spawn. Female bettas still carry the full aggression and territoriality of the species — they are not a peaceful alternative.

Tank mates — the honest truth

This is the section where I am going to disappoint people. Male bettas are territorial, and many individual males simply will not tolerate tank mates regardless of how well you set up the tank. There is no guaranteed combination. The question is not "what tank mates are safe with bettas" but "which tank mates are safest to try with this particular betta, and what is my plan if it goes wrong".

Companions that often work

• Nerite snails — the safest tank mate of all. Bettas ignore them, they eat algae, and they cannot breed in freshwater so populations stay stable.
• Amano shrimp — larger shrimp that most bettas will not mess with. Cherry shrimp are a gamble — colourful ones especially get hunted.
• Pygmy corydoras — small, peaceful bottom dwellers that stay out of the betta's zone. Need a group of at least 6.
• Kuhli loaches — eel-like bottom dwellers, mostly nocturnal, mostly hidden. Very rarely trigger aggression.
• Harlequin rasboras — a calm school can work with a calm betta in 60+ litres. Their copper-brown colour seems to trigger bettas less than flashy species.
• Otocinclus — tiny, peaceful algae grazers that stick to the glass and plants.

Companions to avoid

• Other bettas — male, female, or mixed. Two males will fight to the death. A pair outside of spawning will too.
• Guppies and endlers — colourful males with flowing fins are irresistible targets. Almost guaranteed fin damage.
• Angelfish — both species will target each other eventually.
• Cichlids — territorial overlap is a recipe for disaster.
• Fin nippers — serpae tetras, tiger barbs, black widow tetras. They will shred a betta's fins to ribbons.
• Anything flashy — any fish with a long-finned, brightly-coloured male triggers flaring and attacks.

The neon tetra question

Neons come up constantly because they are popular. A calm male betta in a planted 60-litre tank with a proper school of 10-15 neons often works. An aggressive betta or a smaller group will end in chased, stressed neons and a flaring betta. I have had it work beautifully and I have had to separate them within a week. You are betting on temperament — if it matters that you do not lose either species, do not do it.

The sorority myth

Female betta "sororities" — groups of 5 or more females in a single tank — are marketed everywhere. The truth is that most of them collapse into aggression within a few weeks or months. I have seen a small number work long-term, and they all had the same ingredients: a tank of 80+ litres, dense planting with heavy sight breaks, a large enough group (7+) to diffuse individual aggression, constant keeper observation, and a backup tank ready at a moment's notice.

My honest recommendation: unless you have the tank space, the backup capacity, and the time to intervene, do not try a sorority. A single female betta in a 20-30 litre tank is a beautiful, comfortable fish. She does not need a "family" — she is perfectly happy on her own.

Breeding

Breeding bettas is rewarding and genuinely manageable, but it requires commitment. You will raise 50-200 fry, you will need jars for every male past about 8 weeks of age, and you will need homes for dozens of fish you cannot keep yourself. Think carefully before starting.

Setup

Use a bare-bottomed 40-60 litre tank at 26-27 degrees, 10-15 cm of water depth, and a small floating plant island. Remove filtration or run a very gentle sponge — you need still water for the bubble nest. A piece of styrofoam or indian almond leaf on the surface gives the male a nest anchor point.

Conditioning

Two weeks of high-protein feeding separately, in sight of each other through a glass divider or jar. Live foods — blackworms, brine shrimp, mosquito larvae — bring both fish into peak condition. The female should show clear vertical breeding bars and a plump belly. The male should be building bubble nests actively.

Spawning

Introduce the female in the evening. Expect chasing and a few torn fins — this is normal. The male will entice her under the bubble nest, they wrap bodies, eggs drop, and the male catches each one in his mouth and places it into the nest^[2]. The whole process takes several hours.

After spawning

Remove the female immediately — the male will attack her to protect the nest. The male tends the eggs and fry for the first few days, constantly repositioning them in the nest. Once the fry become free-swimming (roughly 3 days after hatching), remove the male too or he will start eating them.

Raising fry

Feed infusoria or commercial liquid fry food for the first few days, then newly hatched brine shrimp as they grow. Daily small water changes are essential. At 6-8 weeks, males start showing aggression and must be jarred individually for the rest of their lives. This is the reality check — breeding bettas is a big commitment in tank space and time.

Health and disease prevention

A healthy betta is alert, actively cruising or resting with open fins, feeding keenly, and showing strong colour. Signs something is wrong include clamped fins, loss of appetite, lying on the substrate, rapid gill movement, and colour loss.

Common issues

Finrot is the most common betta health problem, and nine times out of ten it traces back to water quality in an under-filtered or under-changed tank. Fins look ragged at the edges, sometimes with a red or black line where tissue is dying. Catch it early and it resolves on its own with pristine water. Catch it late and you will need antibiotic treatment (esha 2000 or interpet anti-internal bacteria are widely available in the UK).

Ich (white spot) shows as tiny white dots on the body and fins. Raise temperature gradually to 28-30 degrees and treat with a proprietary ich medication. Quarantine all new fish for 2 weeks to prevent introducing it.

Velvet is a parasitic infection that gives the fish a dusty gold sheen on the body. Treat with a copper-based medication in a darkened tank.

Dropsy — scales standing out like a pinecone — is rarely treatable. It indicates organ failure, usually from a chronic infection or underlying issue. Quarantine immediately and manage comfortably.

Swim bladder issues — floating sideways, sinking, or struggling to stay level — are often caused by constipation from overfeeding. Fast for 2-3 days, then feed a small piece of cooked, peeled pea. If recurrent, switch to a smaller daily feed or change to a higher-quality pellet.

Prevention

Good husbandry beats medication every time. Cycle the tank properly. Maintain stable temperature. Do 20-25% water changes weekly. Feed appropriately. Quarantine new fish. Observe your betta daily — a change in behaviour is the earliest warning sign of any issue, and catching problems in the first 48 hours is the difference between a quick resolution and a prolonged treatment.

The truth about betta lifespan

Online, you will see betta lifespans stated as anything from 2 to 10 years. The realistic range in a home aquarium is 3-5 years, with 4 being my average and a well-kept fish reaching 5.

The reason so many bettas die young is not that they are short-lived fish — it is that they are usually sold when already 1-2 years old (breeding age), and then kept in conditions that shorten whatever life they had left. A pet-shop betta in an unheated bowl rarely makes it a year. The same fish in a heated 30-litre planted tank will routinely live 3-4 years from purchase.

If lifespan matters to you, buy the youngest fish you can find (a good breeder or specialist will sell juveniles), set up the tank properly before the fish arrives, and stick to a maintenance routine. The fish will do the rest.

UK delivery and acclimation

We ship live fish across the UK with insulated packaging and seasonal heat packs during cooler months. Orders are dispatched Monday to Wednesday for tracked delivery, which keeps time in the box as short as possible.

When your betta arrives, float the sealed bag in your aquarium for 15 minutes to equalise temperature. Then drip-acclimate over 30-45 minutes — bettas are more sensitive to pH changes than many community fish, and a gentle drip acclimation reduces stress significantly. Do not tip the transport water into your tank; net the fish out and release him gently.

It is normal for a newly arrived betta to hide, refuse food, and look pale for the first 24-48 hours. The change in water chemistry, lighting, and surroundings is disorienting. Leave the lights off for the rest of the day, do not feed that evening, and he should be exploring by the following morning. If he is not feeding within 72 hours, test your water first before assuming anything else is wrong.

Why buy from us

Every betta we dispatch has been observed, feeding, and settled before it goes into a box. We do not ship fish straight off the wholesaler's pallet — they spend time in our system first, so you are not paying for a fish that is already stressed from its journey. Each betta is packed individually in a breather bag with adequate water volume, insulated packaging, and a heat pack in cooler months.

We are happy to advise on tank setup before you order. A well-set-up 30-litre tank is a better home for a betta than a show-quality specimen in the wrong kit, and we would rather delay your order than send a fish into conditions we know will stress it. If you are building your first betta tank, browse our betta collection and drop us a line if you have questions.

Answers to common questions

How long can a betta fish live?

With good husbandry, 3-5 years is realistic, and 4 years is a reasonable average. I have had plakats reach 5 years in heated, filtered, planted tanks. Short lifespans usually trace back to unheated bowls or fish that were already old when purchased^[1].

What are the best betta tank mates?

In my experience, the safest options are nerite snails, amano shrimp, pygmy corydoras, and kuhli loaches in a tank of at least 40 litres. A calm male can sometimes share a 60-litre planted tank with harlequin rasboras. Always plan for separation in case your specific betta does not tolerate company.

What size tank does a betta fish need?

Twenty litres minimum, 30-40 recommended. Footprint matters more than height — bettas are shallow-water fish that use horizontal space. A wide 35 by 25 cm tank of 25 litres will keep a betta happier than a tall 30-litre pillar tank.

What is the betta fish lifespan?

The average is 3-5 years, with 4 being realistic for a well-kept fish. Plakats and shorter-finned varieties tend to live longer than extreme show strains because they are not carrying the muscular load of heavy fins through every swim.

How long can betta fish survive without food?

A healthy adult can safely skip food for 7-10 days. For a long weekend (3-4 days) I simply do a large water change before leaving and do not feed at all. For longer trips, arrange pre-portioned feeds for a neighbour rather than trusting an automatic feeder in a small tank.

Can neon tetras live with bettas?

Sometimes. A calm betta in a planted 60-litre tank with 10-15 neons can work. An aggressive betta will chase and stress them. I would only try it with sight breaks, a large school, and a backup plan. See our neon tetra guide for more on neons and their tank-mate compatibility.

How many betta fish can I keep in one tank?

One male per tank, always. Two males will fight to the death regardless of tank size. Female sororities can work occasionally in large, heavily planted tanks but most fail within weeks. If you want multiple bettas, you need multiple tanks.

Do bettas really need a heater?

Yes. They are tropical fish from Southeast Asia and need 24-28 degrees C to thrive^[1]. UK room temperature drops below this for most of the year, and cold water is one of the fastest ways to shorten a betta's lifespan. A reliable thermostatic heater is the single most important kit after the tank itself.

What do betta fish eat?

Bettas are carnivores. A quality betta-specific pellet forms the daily staple, supplemented 3-4 times a week with frozen bloodworm, brine shrimp, or daphnia. Fast one day a week for digestive health. Avoid generic flake food as a main diet^[2].

Why does my betta have torn fins?

Three main causes: sharp decor, jumping into a hard lid, or finrot from poor water quality. Run the "tights test" on your decor (if tights snag on it, fins will too), ensure your tank has a secure lid, and test ammonia/nitrite if the edges look ragged rather than cleanly torn.

Are bettas good for beginners?

Yes, provided you start with a proper 20-30 litre cycled tank with a heater and gentle filter. A single male betta is genuinely one of the most rewarding first fish — they have personality, recognise their keeper, and show behaviour you can get invested in. The "hard to keep" reputation comes from the bowls they are so often sold in, not from the fish itself.

What is the difference between a plakat and a halfmoon betta?

Plakats are short-finned and closer to the wild form. Halfmoons have a tail that spreads to a full 180-degree arc when flared. In practical terms, plakats are more active, swim better, are less prone to fin damage, and tend to live longer. Halfmoons are stunning for photography but carry welfare costs from the heavy fin load.