Crowntail Female Betta (Betta splendens)

Choose the exact offer

The Crowntail Female Betta (Betta splendens) is a domestic form of a freshwater fish in the family Osphronemidae. The wild species occurs in Asia’s Mekong basin, while this named Crowntail form belongs in a heated aquarium rather than being treated as a wild-locality fish. FishBase records a maximum length of 6.5 cm, so the aquarium must be planned around that adult size from the beginning.

This fish suits a prepared keeper who can provide a mature, filtered and covered aquarium with shade, plants, refuges, gentle water movement and clear access to the surface. Solitary housing is the safest default because ornamental Betta splendens are territorial and tolerance of community companions is the exception rather than the expected result. The setup and compatibility decisions make this an intermediate-care fish rather than a simple addition to any community aquarium.

One purchase supplies one Crowntail Female Betta in the size selected from the live size selector. The labels are 2–3 cm and 3–4 cm. The size you select is the size supplied, not the adult size. Both sizes need the full heated, filtered and furnished adult aquarium before arrival; neither belongs in a temporary bowl, jar or reduced setup.

Sex is guaranteed only when the exact product or selected option explicitly states male or female. This Crowntail Female Betta listing is sold as female. That designation does not promise a particular temperament or make routine housing with another Betta safe.

The gallery images are representative, based on reference photographs of this species, so colours can look slightly different from the live animal.

For other domestic forms, browse the Betta collection. Packing, acclimatisation and claim steps are set out in the current delivery and Live Arrival Guarantee policy.

Plan around mature proportions

This is a domestic Crowntail form of Betta splendens, the fish widely called a Betta or Siamese fighting fish. Crowntail identifies the named domestic form rather than a separate species. The NCBI taxonomy entry recognises Betta splendens, while FishBase places it in the family Osphronemidae.

FishBase records a maximum of 6.5 cm total length for male or unsexed fish. Use 6.5 cm as the adult planning figure throughout this page. Seriously Fish separately lists 7 cm standard length, so allow clear swimming and resting space rather than designing the layout tightly around the dispatch measurement.

Domestic colour, fin and body traits vary substantially. A genome-wide study of domestic Betta diversity describes complex variation in colour, fins, body size and behaviour. Use the fish’s own appetite, breathing, posture and swimming pattern as daily reference points instead of treating colour intensity or one fin shape as a welfare score.

The wild species occurs in Asia’s Mekong basin, but this offer is a domestic aquarium form. Do not use the wild distribution to infer the birthplace, age, pedigree or previous conditions of an individual fish.

Check the core setup before ordering

Seriously Fish gives a 45 × 30 cm aquarium base, approximately 41 litres, as large enough for a single male or pair of Betta splendens. For this female, use that footprint and volume as the practical solitary plan. A longer, furnished footprint gives room for cover, open movement and a gentle flow gradient.

The same species profile gives 22–30°C, pH 6.0–8.0 and 1–15 dGH for aquarium care. Tropical Fish Co uses a stable 26–28°C routine target for a typical domestic Betta splendens. Measure that target with a separate thermometer rather than assuming the heater dial matches the water.

We class this domestic form as intermediate care. The aquarium must be cycled, heated, covered and routinely tested, while territorial behaviour requires more planning than a simple peaceful-community label suggests. Read the complete Betta fish care guide before finalising equipment.

Mature the aquarium before arrival

A clear-looking aquarium is not automatically ready for a fish. The RSPCA explains that a working biological filter supports bacteria that process toxic ammonia into nitrite and then nitrate. Establish that biological function before the Betta arrives and confirm it with aquarium tests.

Use a pre-arrival gate

1. Fill and run the aquarium with its heater, filter, lid and intended furnishings in place.
2. Mature the biological filter before adding livestock.
3. Confirm ammonia is 0 mg/L and nitrite is 0 mg/L.
4. Check the separate thermometer over several days rather than relying on one reading.
5. Measure pH and general hardness so they can be compared with the stated aquarium range.
6. Confirm that the fish can reach an open part of the surface beneath the secure lid.
7. Make sure plants and refuges do not create trapping gaps or obstruct the filter.

If ammonia or nitrite is detectable, delay the planned introduction and continue maturing the system. Adding a fish to make the cycle progress exposes the animal to toxic waste and gives the filter more waste than its bacterial population is ready to process.

The first tropical aquarium guide explains how to prepare and mature a new setup. Record dated test results, equipment adjustments and maintenance; a short written history makes it easier to distinguish a stable pattern from a sudden change.

Check the real aquarium, not only its label

Nominal capacity and usable water volume are not identical once substrate, wood, plants and an air gap are included. Confirm the internal footprint as well as the litre label. A 45 × 30 cm base with approximately 41 litres is the practical target here, and more space can make temperature and waste trends easier to manage.

Run a final readiness rehearsal before choosing the dispatch date. Feed the empty cycle according to the maturation method being used, confirm that ammonia and nitrite return to 0 mg/L, and check the heater at the coolest part of the day. Open the lid as you would during feeding, inspect every equipment gap, then restore it securely. This rehearsal tests the whole routine rather than one isolated water sample.

Hold stable water values

OATA’s Siamese fighting fish sheet gives 20–28°C, pH 6.0–8.0 and 4–12 dGH as broad group guidance, not a species-specific optimum. It also calls for ammonia and nitrite at 0 mg/L and nitrate no more than 20 mg/L above the normal tap-water level. For this domestic Betta splendens, use the Seriously Fish species-profile range of 22–30°C, pH 6.0–8.0 and 1–15 dGH, with 26–28°C as our stable routine temperature target.

Separate range checks from routine targets

Test the aquarium itself because UK tap-water chemistry varies. Treat replacement tap water with a suitable conditioner for chlorine or chloramine, then match its temperature before a partial water change. Stability matters: do not alter pH or hardness merely to hit the middle of a range when the aquarium is already within it.

Use the aquarium water-chemistry guide to understand what each test measures. The water matcher can then compare measured aquarium values with the stated ranges.

If a result changes sharply, repeat the test correctly and review recent water changes, conditioners, feeding and equipment changes. Correct the cause gradually unless toxic ammonia or nitrite requires prompt water-quality action.

Use trends to guide decisions. For example, a pH reading within 6.0–8.0 does not need adjustment simply because it differs from last week by a small amount, but a sharp shift alongside altered behaviour deserves a repeat test and a review of recent work. When ammonia or nitrite appears, prioritise restoring safe water quality and checking biological filtration rather than trying to change several unrelated values at once.

Balance filtration, cover and surface access

Betta splendens naturally uses sluggish environments, so strong water movement should be avoided. Biological filtration still remains essential. Choose a filter that processes waste while allowing the fish to swim, feed and rest without continually resisting the outlet.

For an aquarium of approximately 41 litres, Seriously Fish suggests a filter rated around 80–125 litres per hour. Treat that as a starting equipment range, then judge the result in the furnished aquarium. Plants, outlet direction, media loading and the shape of the tank all change how the flow reaches the fish.

Read the fish’s response

• If the fish is repeatedly displaced from a resting position, diffuse or redirect the outlet while keeping the biological filter running.
• If food is swept away before it can be eaten, create a calmer feeding area rather than adding excess food.
• If debris collects throughout still areas, adjust circulation gently without turning the whole aquarium into fast water.
• If the intake presents a trapping risk, fit an appropriate guard and check that it does not become blocked.

Bettas possess a labyrinth organ and can breathe atmospheric air. This ability does not replace filtration or clean water. Keep an unobstructed route to the surface and use a secure cover that reduces escape risk.

Build useful shelter

A shaded, well-planted aquarium with surface cover suits this species. Tall stems, floating plants and tropical lilies are examples in the species profile; driftwood and attached plants can add structure lower down. Small smooth refuges can also be used, provided every opening is large enough for safe entry and exit.

Leave part of the surface open for breathing and feeding. Check that furnishings do not have rough points, unstable gaps or positions that could pin the fish against equipment. The goal is a choice between shelter and open movement, not a packed layout that prevents observation or maintenance.

Assess flow in more than one place. Watch the feeding area, a sheltered resting point and the route to the surface. If one area is calm but the fish must cross a forceful outlet to breathe or feed, redirect the current. If reducing the outlet creates widespread debris accumulation, rebalance the layout and circulation instead of switching off filtration.

Feed complete food with measured variety

Seriously Fish describes wild Betta splendens as likely to prey on aquatic and terrestrial invertebrates. In the aquarium, dried foods are normally accepted once recognised as edible, while small live or frozen foods such as daphnia, Artemia and bloodworm can support variety and condition.

Use a suitably sized complete Betta pellet or quality aquarium flake as the nutritional base. OATA recommends feeding only what the fish can consume within a few minutes, once a day. Remove uneaten food so it does not decompose and add waste to the water.

Adjust by observation

Food brands differ in particle size and energy density, so one fixed pellet count cannot suit every product. Begin with the manufacturer’s measured guidance, watch the fish eat and review body condition over time. Reduce the portion when food remains after a few minutes rather than relying on the filter to collect it.

If the fish repeatedly fails to take a food, check that the particle is appropriately sized and offer the recognised complete food. A persistent change in appetite should trigger checks of temperature, ammonia, nitrite and the fish’s wider behaviour rather than repeated feeding attempts.

Overfeeding affects both body condition and water quality. Pre-measure portions when several people care for the aquarium, and keep treats as variety rather than replacing the complete nutritional base.

A practical feeding review compares three observations: whether the fish recognises and swallows the food, whether any remains after a few minutes, and whether body condition stays steady over time. If food is swallowed promptly but leftovers remain, reduce the next measured portion. If appetite changes suddenly, test the aquarium before changing several foods, because the feeding response can be an early sign that the wider setup needs attention.

Use a weekly maintenance rhythm

OATA strongly recommends changing 25% of the water at least once a week and testing the aquarium at least weekly. Use that as the starting routine, then keep dated results so the maintenance schedule responds to the aquarium’s real trend.

Every day

• Check the separate thermometer and confirm that the filter is operating.
• Look for clear access to the surface and make sure the lid remains secure.
• Observe appetite, breathing, swimming, posture, colour and fin condition.
• Remove uneaten food after the feeding period.

At least once a week

• Test ammonia and nitrite and maintain both at 0 mg/L.
• Test nitrate and compare the result with previous readings and the tap-water baseline.
• Change 25% of the water using conditioned replacement water at a matched temperature.
• Siphon accessible solid waste without dismantling the entire planted layout.
• Inspect the filter for blockages and check that its outlet still creates gentle movement.

When filter media needs cleaning, rinse it lightly in aquarium water removed during the partial water change. Do not run it under the tap because chlorine or chloramine may kill the beneficial bacterial population established in the media.

Review the first month

During the first week, compare each day’s appetite and activity with the previous day and test immediately if behaviour changes. By the end of the first month, review the temperature record, nitrogen-cycle results, body condition and use of the layout. Adjust one feature at a time so its effect can be observed.

A larger water change is not a substitute for investigating persistent waste readings. Review feeding, hidden debris, stocking, filter condition and recent changes whenever ammonia, nitrite or nitrate moves away from its normal pattern.

Keep maintenance repeatable by using the same test method, recording readings before the water change and noting the volume replaced. If nitrate rises faster than usual while feeding is unchanged, inspect for trapped waste and reduced filter flow. If the trend remains stable and ammonia and nitrite stay at 0 mg/L, continue the routine rather than repeatedly dismantling a settled aquarium.

Introduce and observe the fish carefully

Prepare and test the aquarium before the fish arrives. Confirm 0 mg/L ammonia, 0 mg/L nitrite, a stable 26–28°C routine temperature and measured pH and hardness. Keep the aquarium quiet enough to observe breathing, posture and swimming after introduction.

Use first-week checkpoints

OATA advises watching for changes in swimming, colour, temperament, breathing, appearance, condition and feeding. One sign alone is not a diagnosis. Begin with measured water quality and a review of recent additions, maintenance, food and equipment.

The MSD Veterinary Manual’s aquarium-fish guidance emphasises aquarium history, water analysis and appropriate diagnostic work. Avoid combining medicines or changing temperature in response to a guessed condition. When a change is severe, persistent or unexplained, seek qualified aquatic help; OATA maintains a UK fish-vet directory.

Keep a short log of test results, appetite and visible changes. A dated pattern helps distinguish a stable individual trait from deterioration and gives an aquatic professional more useful context if assessment becomes necessary.

During the first day, prioritise quiet observation over repeated rearrangement. Confirm that the fish can reach the surface, find a sheltered resting place and move away from the filter outlet. Over the next several days, compare feeding response and swimming with the first settled observations. If a change appears, write down when it began and what happened beforehand; this creates a useful sequence for water testing and health assessment.

Keep one Betta by default

Seriously Fish describes ornamental Betta splendens as highly aggressive and advises that only one individual can be kept per aquarium in most cases. It recommends keeping the species alone because tolerance of other species is the exception rather than the expected result. Use one Crowntail Female Betta as the default social plan.

Female sex does not turn the fish into a guaranteed community animal. OATA discusses female groups in larger, densely planted aquariums, but a group formula does not override individual territorial behaviour. Do not buy multiple females on the assumption that their sex alone will make the arrangement stable.

Avoid routine high-risk combinations

• Avoid housing this fish with another Betta as an ordinary permanent arrangement.
• Avoid boisterous or aggressive fish; OATA specifically excludes them from female Betta community planning.
• Avoid using a male as a permanent companion. Seriously Fish describes usual practice as keeping males and females separately unless breeding.

The RSPCA’s guidance on keeping fish together notes that male Bettas may fight their own kind and that compatibility requires research into the animals being combined. More space does not make a known aggressive pairing automatically safe.

Give solitary housing real structure

Keeping one fish does not mean keeping it in a bare container. Use the full 45 × 30 cm footprint, plants, shade, refuges, gentle flow and open surface access. This gives the fish environmental choices while making appetite, waste and health changes easier to monitor.

Any attempted community must begin with a separate, heated and cycled fallback aquarium. Without somewhere suitable to move an incompatible animal, observation alone cannot protect either fish once persistent chasing, exclusion or injury begins.

Use a simple decision test before adding any animal: if the plan depends on this female being unusually tolerant, it is not a reliable default. Solitary housing already meets the social plan recommended by the species profile. A community should therefore add no compromise to water quality, feeding access, resting space or surface access, and it must remain reversible from the first day.

Screen every community plan before mixing fish

No companion species is automatically safe with a Crowntail Female Betta. Individual temperament varies, and the other animal’s behaviour can be equally important. Screen the complete adult community rather than choosing from a universal tank-mate list.

Seriously Fish notes that some small cyprinids and loaches from similar environments may sometimes be considered, but says careful research is essential and that keeping the Betta alone is best in most cases. Those broad groups are not promises for a particular species, aquarium or individual.

Act on persistent pressure

OATA identifies changes in aggression, hiding, feeding, colour, breathing and swimming as reasons to investigate. If one fish controls the feeding area, pursues the Betta repeatedly or prevents normal use of cover and surface access, separate them rather than waiting for visible injury.

Brief investigation of a new neighbour does not establish long-term compatibility. Continue checking appetite, body condition, fins, resting places and use of the whole aquarium through the following days and weeks. Territorial behaviour can change after a layout change or as individuals settle.

The honest limit is simple: a well-screened combination may still fail. Build the community around compatible adult requirements and maintain a practical separation plan throughout.

Work through the screen in order. First reject any animal whose adult water or space requirements conflict with the Betta setup. Next reject boisterous, aggressive or fin-nipping behaviour. Then check whether feeding zones and surface routes can remain open. Only after those gates pass should an introduction be considered, and the heated, cycled fallback must already be functioning rather than assembled after conflict begins.

Answer the key buyer questions

How big does a Crowntail Female Betta get?

A Crowntail Female Betta reaches the FishBase maximum recorded length of 6.5 cm. Plan the aquarium around that adult figure rather than the 2–3 cm or 3–4 cm dispatch size.

What size aquarium does a Crowntail Female Betta need?

Use the Seriously Fish species-profile footprint of 45 × 30 cm, approximately 41 litres, with plants, shade, gentle mature filtration, a secure lid and open surface access.

How many Betta splendens should I keep together?

Keep one fish by default. Seriously Fish advises that only one ornamental Betta splendens can be kept per aquarium in most cases, and routine housing with another Betta should be avoided.

Is a Crowntail Female Betta suitable for beginners?

It can suit a careful beginner with a fully matured aquarium, but Tropical Fish Co classes it as intermediate because it needs stable heat, tested water, gentle filtration and deliberate compatibility planning.

What does Betta splendens eat?

Feed a suitably sized complete Betta pellet or quality flake as the nutritional base. OATA’s Betta guidance says to feed once daily in an amount eaten within a few minutes, while Seriously Fish lists daphnia, Artemia and bloodworm as live or frozen variety.

What temperature and pH does it need?

Keep it within the Seriously Fish species-profile range of 22–30°C and pH 6.0–8.0, with 1–15 dGH hardness. Tropical Fish Co uses a stable 26–28°C routine target for a typical domestic Betta splendens.

Is it aggressive or likely to nip fins?

It is territorial and should be kept alone by default. Avoid another Betta and avoid boisterous or aggressive fish; screen any proposed companion for fin-nipping risk and separate the animals if chasing, exclusion or injury occurs.

Which kinds of animals can it live with?

Seriously Fish says some small cyprinids and loaches from similar environments may sometimes be considered, but solitary care is best in most cases. Check adult space, water overlap, activity, feeding competition and fin interaction, with a heated, cycled separation aquarium ready.

How does it arrive alive in the UK?

Start filming every delivery continuously while the parcel is still sealed, then record it being opened with the fish still inside the sealed bag. Someone must be present to receive the parcel. Float the bag for 20–30 minutes before releasing the fish, and never pour the bag water into the aquarium.

Consult the care references

• FishBase: Betta splendens — scientific identity, family, distribution, environmental values and maximum recorded length.
• Seriously Fish: Betta splendens — aquarium footprint, water ranges, furnishing, diet and behavioural guidance.
• OATA: Siamese fighting fish care — UK group guidance for water quality, feeding, maintenance and observation.
• RSPCA: aquarium environment — biological filtration and waste processing.
• NCBI Taxonomy: Betta splendens — scientific-name reference.
• Kwon et al. 2022 — domestic Betta colour, fin, body and behavioural diversity.
• RSPCA: keeping pet fish together — compatibility and same-kind aggression considerations.
• MSD Veterinary Manual: management of aquarium fish — water-led health investigation and diagnostic context.
• OATA: find a fish vet — UK directory for aquatic veterinary help.