Butterfly Halfmoon Betta Male (Betta splendens)

Know what this offer contains

The Butterfly Halfmoon Betta Male (Betta splendens) is a domestic ornamental labyrinth fish in the family Osphronemidae. The wild species is native to central Thailand and the lower Mekong, while domestic forms have a complex breeding history. FishBase records a maximum length of 6.5 cm. This male suits a prepared keeper who can provide a mature, heated, covered and furnished aquarium, gentle filtration, clear surface access and solitary housing.

The Halfmoon butterfly wording identifies the domestic ornamental form rather than a separate species. Domestic Bettas show extensive variation in colour and finnage, and genome research into domestic Betta diversity describes a complex breeding history behind those traits. A colour or fin label does not determine age, temperament, pedigree or wild origin.

Betta splendens Regan, 1910 belongs to the family Osphronemidae. Its specialised labyrinth organ allows it to take atmospheric air at the surface. That ability makes unobstructed surface access essential while leaving the need for a mature biological filter, stable heat and clean water unchanged.

Purchase and gallery details

One purchase supplies one animal. Sex is guaranteed only when the exact product or selected option explicitly states male or female. This Butterfly Halfmoon Betta Male listing is sold as male.

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

Plan around adult size, water and space

FishBase records a maximum of 6.5 cm total length for male or unsexed Betta splendens. Seriously Fish separately uses 70 mm standard length as its aquarium-planning reference. Plan every route, shelter and equipment gap around the 6.5 cm adult figure while allowing room for the male’s extended ornamental fins.

OATA’s group-level Betta guidance recommends at least 20 litres for one male; this is not a species-specific optimum. The Seriously Fish species profile gives a 45 × 30 cm base, or roughly 41 litres, as large enough for a single male or pair and rejects tiny aquaria and jars. Use at least 20 litres for this male, with the larger footprint offering more usable space for cover, open routes and gentle flow. Account for the real filled volume after substrate, wood and equipment are added.

Keep a typical domestic fish steadily at 26–28°C. The overlapping pH range across FishBase, Seriously Fish and OATA is 6.0–8.0, while their overlapping general-hardness range is 5–12 dGH. Ammonia and nitrite must remain at 0 mg/L. Stability matters more than moving the aquarium towards an edge of any range.

We classify this fish as intermediate care. A prepared beginner can keep one, but cycling, heat, surface access, gentle flow, measured feeding and territorial behaviour all need active management. Read our complete Betta fish care guide before finalising the aquarium.

Build usable space with shade, shelter and safe routes

Start with the aquarium’s internal footprint and actual filled volume, not only the capacity printed on its box. A nominal 20-litre aquarium loses water volume to substrate, furnishings and the air gap beneath the lid. A broader 45 × 30 cm base, or an equivalent aquarium of about 41 litres, gives more room to arrange shelter without blocking every swimming route.

Seriously Fish describes a well-planted, shady aquarium with plenty of surface cover as the preferred layout for Betta splendens. Tall stem plants, floating plants and tropical lilies can create overhead cover, while Cryptocoryne, Microsorum and Taxiphyllum are among the examples it names. Driftwood can carry attached plants and divide the aquarium visually. Plant choice remains flexible: the important functions are shade, refuge, resting structure and a clear route to the surface.

Arrange the layout in layers

Inspect every furnishing before use. Sharp points, abrasive edges and narrow openings can damage fins or trap an inquisitive fish. Secure wood, stones and equipment so routine maintenance cannot make them shift. Shelter should create choices rather than confine the fish to one corner.

Dried leaf litter may add cover, and Seriously Fish notes that decomposition encourages microbe colonies that can become a secondary food source for fry. In a display aquarium, add only aquarium-safe leaves and remove material if it begins to obstruct flow, surface access or maintenance. Leaf litter does not replace measured feeding or water changes.

Avoid strong water movement. Watch whether the male can leave the filter return, reach food and rest without being pushed across the aquarium. If the current dominates the whole tank, diffuse or redirect the outlet while preserving continuous filtration. The goal is gentle circulation with calm choices, not stagnant water.

Cycle the filter and protect surface access

A Betta aquarium must be biologically mature before the fish arrives. The RSPCA explains why aquarium filtration is vital: fish release toxic ammonia, beneficial bacteria convert it to nitrite and then to the safer end product nitrate. Clear water alone does not show that this biological process is ready.

Complete a fishless cycle and test the result. Ammonia and nitrite must both read 0 mg/L before the planned transfer. If either is detectable, continue maturing and managing the system rather than using the fish to finish the cycle. Our first tropical aquarium guide sets out the preparation sequence for the filter, heater, tests and furnishings.

Choose flow the fish can use

For an aquarium around 41 litres, Seriously Fish suggests considering a filter rated at roughly 80–125 litres per hour. Treat that rating as an equipment screen rather than a guarantee of gentle conditions: outlet design, media condition and the position of decor change how the current feels inside the aquarium. The male should be able to hold position, feed and rest without continual effort.

• Run biological filtration continuously.
• Diffuse or redirect a narrow jet if it pushes the fish away.
• Keep an area of gentle surface movement for gas exchange.
• Leave calm resting zones without creating dead areas full of waste.
• Guard openings that could catch fins or draw the fish against an intake.

Keep the surface reachable

Bettas use a labyrinth organ to breathe atmospheric air, so leave a clear route to the surface and a small air space below a secure cover. Floating plants can provide useful shade, but thin them before they form a complete barrier. The lid should reduce escape risk without sealing away the air space the fish needs.

An occasional surface breath is part of the fish’s biology. A sudden change to persistent surface hanging, rapid gill movement, loss of balance or reduced appetite calls for immediate checks of temperature, ammonia, nitrite and filter operation. Do not switch off essential filtration merely to reduce current; adjust the outlet or equipment while keeping the biofilter working.

Hold stable heat and measured water chemistry

Keep a typical domestic Betta splendens steadily at 26–28°C, pH 6.0–8.0 and 5–12 dGH. The chemistry figures are the overlap of FishBase’s environmental values, the Seriously Fish aquarium range and OATA’s Betta guidance; the temperature target is Tropical Fish Co’s practical routine within the published ranges.

Use a thermostatic aquarium heater and check the actual water with a separate thermometer. A thermostat setting is a control instruction, while the thermometer shows the result. Check at different times during the aquarium’s first week because room heating, cold nights, direct sunlight and warm weather can change the water around the set point.

Do not alter pH or hardness merely to hit the centre of a range. Test the aquarium and source water, then favour consistency and gradual matching. UK tap water varies, and chlorine or chloramine must be neutralised with a suitable aquarium conditioner before replacement water enters the tank. Use our water chemistry guide to understand each measurement, then compare your readings using the aquarium water matcher.

When a reading changes unexpectedly, confirm it with a fresh test before making a large correction. Review recent water changes, heater operation, filter flow and anything added to the aquarium. Adjust prepared replacement water gradually; a sudden move between two acceptable values can still create avoidable stress.

Feed measured portions once daily

FishBase records zooplankton, mosquito larvae and other insect larvae in the wild diet of Betta splendens. Seriously Fish likewise describes the species as likely to prey on aquatic and terrestrial invertebrates. Captive fish normally learn to accept dried foods, while small live or frozen foods such as Daphnia, Artemia and chironomid larvae can support colour and condition. Bettas are particularly prone to obesity, so portion control matters.

Use a suitably sized, complete Betta pellet or quality aquarium flake as the nutritional base. Live or frozen daphnia, small bloodworm or similar appropriately sized invertebrate foods can provide variety, but a treat should not replace a balanced staple. Choose particles the fish can take cleanly and remove leftovers before they break down.

For the schedule, OATA’s Betta guidance is broad: feed once a day and offer only what the fish can eat within a few minutes. Food brands differ in pellet size and energy density, so a universal pellet count or a portion calculated from the fish’s eye is unreliable. Begin with the food maker’s measured guidance, watch body condition and reduce the amount if food remains.

Overfeeding affects both the fish and the aquarium. Excess energy can contribute to obesity, while uneaten food decomposes and increases the load on the biological filter. Record what is fed during the first month so appetite, body condition and water-test trends can be compared rather than guessed.

Small insects are another option named by Seriously Fish, provided they are appropriately sized and prepared as described there. Keep food sources controlled and hygienic. Never collect live foods from water that may carry pollutants, parasites or unwanted animals into the aquarium.

Introduce the fish to a ready aquarium

Finish every setup decision before the fish arrives. The aquarium should meet the chosen volume and footprint, the heater should hold 26–28°C, the filter should run gently and ammonia and nitrite should both test at 0 mg/L. Check the lid, air space, surface route, shelters and intake openings while the tank is still easy to adjust.

Use a pre-arrival gate

• The aquarium is at least 20 litres, with a larger 45 × 30 cm plan preferred where practical.
• The biological filter is mature and running continuously.
• Temperature is stable at 26–28°C.
• Ammonia and nitrite are both 0 mg/L.
• pH and hardness have been measured rather than assumed.
• Replacement water has been treated for chlorine or chloramine.
• The aquarium contains shade, safe refuge and clear surface access.
• No other male Betta shares the aquarium.

Follow the arrival procedure

1. Be present to receive the parcel; live fish cannot be left unattended.
2. Start filming before opening, with the parcel still sealed and the outer box visible.
3. Open the parcel in one continuous take and show the fish still inside the sealed bag before anything is disturbed.
4. Float the bag for 20–30 minutes before releasing the fish.
5. Never pour the bag water into the aquarium.

Read the current delivery and Live Arrival Guarantee policy before the delivery date. Keep the continuous video with your order details. Send both if a Live Arrival Guarantee claim is needed.

Watch the first hours

Allow the male to locate the surface and shelter. Observe whether he can move away from the filter outlet and reach the surface without struggling. Check that no opening permits escape and that floating plants have not shifted into a complete surface barrier.

Continue the established once-daily feeding plan rather than compensating for travel with a large meal. Note whether food is recognised, but assess appetite alongside breathing, posture and water tests. A single observation should not become a diagnosis.

Use weekly maintenance to preserve stability

OATA strongly recommends a 25% partial water change at least once every week and testing the aquarium at least weekly. Treat that as the routine starting point, then use test trends, feeding and visible waste to decide whether the aquarium needs more frequent attention. A solitary fish still produces waste, and clear water can contain dissolved pollutants.

Follow one repeatable weekly sequence

1. Observe the fish’s breathing, posture, appetite, fins and swimming before disturbing the aquarium.
2. Record temperature, ammonia, nitrite, nitrate and pH.
3. Remove 25% of the water while siphoning accessible solid waste.
4. Prepare replacement water with conditioner and match its temperature closely.
5. Inspect the filter for blocked flow, but clean only what needs attention.
6. Check the lid, cables, heater position, intake guard and surface route.
7. Return the aquarium to its normal routine and confirm that equipment restarts.

If the filter needs cleaning, do not run it under the tap. OATA advises lightly rinsing dirty media in the aquarium water removed during the partial water change, which reduces the amount of beneficial bacteria lost. Avoid replacing all mature media at once unless a specific safety problem makes replacement necessary.

Stagger non-urgent changes. Replacing substrate, cleaning all filter media, moving every furnishing and changing water chemistry on the same day removes useful continuity and makes the cause of any later problem harder to identify. Make one planned adjustment, observe its effect and retain written test results.

Respond to health changes methodically

Learn the individual fish’s usual appetite, breathing, posture, swimming and resting places during the first weeks. OATA advises watching for altered swimming, darker or paler colour, unusual hiding or aggression, faster or slower gill movement, white spots, fluffy growths, lost fins or scales, changing body condition and reduced feeding.

These signs tell you to investigate; they do not identify one disease. The MSD Veterinary Manual’s aquarium-fish guidance places aquarium history, water analysis and appropriate diagnostic work at the centre of health assessment. Avoid choosing a medicine from one visual similarity or combining treatments without a clear reason.

Work through the aquarium first

1. Confirm temperature with the separate thermometer.
2. Test ammonia, nitrite, nitrate and pH.
3. Check heater, filter flow and surface access.
4. Review recent additions, maintenance and feeding changes.
5. Inspect furnishings and the intake for a possible physical cause.
6. Compare the fish with its own normal behaviour and earlier photographs.

Correct an urgent water-quality fault with appropriate husbandry, but do not assume that cleaner water identifies the cause of every symptom. Severe, persistent or worsening signs need experienced aquatic support. OATA maintains a UK fish-vet directory for locating veterinary help.

Keep one male as the default social plan

Plan this Butterfly Halfmoon Betta Male as the only Betta in his aquarium. Seriously Fish says Betta splendens is best kept alone and that only one individual can be kept per tank in most cases. It describes community tolerance as the exception rather than the expected outcome.

Avoid housing two males together. OATA warns that males are highly aggressive and may fight until one is severely injured or killed. The RSPCA’s fish compatibility guidance also recognises that male Bettas may fight their own kind. A bigger aquarium, temporary calm or added decoration does not turn direct male cohabitation into a safe plan.

Keep male and female Bettas separate

Seriously Fish describes the usual practice as maintaining males and females separately unless breeding. Avoid routine permanent housing with a female. Breeding behaviour can involve aggression and requires specialist planning, cover, observation and separate accommodation; this offer is for one male rather than a pair.

Neighbouring aquaria also need thoughtful placement. Prevent direct contact, jumping routes and prolonged exposure to another male if repeated display stops the fish from feeding, resting or exploring normally. Each aquarium needs its own suitable volume, heat, filtration, cover and surface access.

A solitary plan does not mean a bare environment. Plants, shade, shelters, open swimming routes and regular observation provide the structure this fish needs without adding another animal whose behaviour may create conflict.

Screen every community plan before mixing fish

No species name guarantees compatibility with a male Betta splendens. Seriously Fish notes that some small cyprinids and loaches from similar environments may be suitable, but proper research is essential and most individuals are best maintained alone. OATA advises considering only very placid companions because male Bettas can become targets of intense fin-nipping.

A 20-litre aquarium should be treated as a solitary male setup. Do not add companions merely because their bodies fit into the remaining space. A community aquarium must meet the adult space, social-group, substrate, feeding and water needs of every species, not only the Betta’s minimum.

Observe the first interactions and continue watching after the novelty passes. Persistent chasing, repeated biting, blocked access to food, continual hiding, damaged fins or a fish pinned to one area all require separation. Do not wait for visible injury when the behaviour already shows that the arrangement is failing.

Uncertainty applies in both directions: the Betta may attack another animal, or a companion may harass his extended fins. Plants and sight breaks can reduce exposure, but they do not guarantee peace. Keep the solitary aquarium as the default whenever every screen cannot be passed.

If you are comparing ornamental forms rather than choosing companions, browse the Betta collection. Different male Betta products are alternative choices for separate suitable aquaria, not a suggested group.

Answer the key questions before choosing

How big does a Butterfly Halfmoon Betta Male get?

The Butterfly Halfmoon Betta Male reaches a recorded maximum of 6.5 cm total length according to FishBase. Plan the aquarium, shelters and equipment gaps around that adult size and the space occupied by its extended fins.

What size aquarium does this Betta need?

Use at least 20 litres for one Betta splendens male under OATA’s group guidance. Seriously Fish gives a 45 × 30 cm base, about 41 litres, as a stronger species-focused plan; furnish it, keep the flow gentle and leave the surface accessible.

How many Butterfly Halfmoon Betta Males can I keep together?

Keep one Butterfly Halfmoon Betta Male per aquarium. Male Bettas may fight until one is severely injured or killed, so avoid housing two males together and keep males and females separate unless temporarily managed in a specialist breeding plan.

Is this Betta suitable for a beginner?

A Butterfly Halfmoon Betta Male can suit a careful beginner once a proper aquarium is cycled and ready. At least 20 litres, a mature filter, thermostatic heater, separate thermometer, secure lid, safe furnishings and regular water tests must be in place first.

What does Betta splendens eat?

Feed Betta splendens a measured complete Betta pellet or quality aquarium flake once daily, giving only what is eaten within a few minutes. Add small live or frozen invertebrate foods such as daphnia, Artemia or bloodworm as variety.

What temperature and pH does this fish need?

Keep the Butterfly Halfmoon Betta Male steadily at 26–28°C and pH 6.0–8.0. The pH range overlaps FishBase, Seriously Fish and OATA guidance; maintain 5–12 dGH, with ammonia and nitrite at 0 mg/L.

Is a Butterfly Halfmoon Betta aggressive or likely to nip fins?

The male is territorial towards other Bettas and may treat fish with rival-like body shapes or trailing fins as competitors. Avoid other male Bettas, routine permanent housing with a female, rival-like fish, boisterous fish and persistent fin-nippers.

Which animals can Betta splendens live with?

Most Betta splendens are best kept alone. Seriously Fish says some small cyprinids and loaches may be suitable only after screening adult space, water overlap, social needs and behaviour; prepare a mature separation aquarium before attempting a community.

How does this fish arrive alive in the UK?

Someone must be present to receive it. Film every delivery continuously from the sealed parcel as it is opened, showing the fish still in the sealed bag; then float the bag for 20–30 minutes and never pour the bag water into the aquarium.

References for identity, husbandry and welfare

• FishBase: Betta splendens — taxonomy, family, distribution, environmental values, diet, behaviour and maximum recorded length.
• Seriously Fish: Betta splendens — aquarium footprint, water, furnishing, diet and behaviour.
• OATA: Siamese fighting fish — UK Betta husbandry, feeding, maintenance and compatibility guidance.
• RSPCA: aquarium environment — filtration and biological waste processing.
• NCBI Taxonomy: Betta splendens — scientific identity.
• Kwon et al.: domestic Betta diversity — genetics of domestic colour, fin and body traits.
• RSPCA: keeping pet fish together — compatibility and male Betta aggression.
• MSD Veterinary Manual: aquarium fish management — water analysis, history and diagnosis.
• OATA: find a fish vet — UK aquatic veterinary directory.