Twoline Skiffia (Skiffia bilineata)

What You Receive

Current sale unit

One selection adds one live fish to the basket. The supplied length is approximately 2-3 cm, with normal biological variation possible. The current product has a single default option and our stock records do not specify sex, locality or a pair. This listing therefore makes no promise that the individual will be male, female, mature, gravid or from a named population.

Listing detail	Current meaning	Not promised
Quantity 1	One live fish	Not a pair, trio or colony
Approximate supplied size	About 2-3 cm	Not an exact measured length
Sex	Unsexed	No male or female guarantee
Origin detail	Species identity only	No collection locality or population code
Gallery	Four representative illustrations	Not exact-stock photographs
Availability	Controlled by the live variant inventory	Not reserved until checkout completes

Why the old female wording is not used

The present our stock records offer Skiffia bilineata at 2-3 cm without a sex designation, while Shopify has no sex-selection option. Customer-facing content must follow the current product contract.

Planning the group

The fish is offered singly so an experienced keeper can choose the number appropriate for an existing group. A new setup should be planned for at least six of the same species. Do not buy one as a permanent solitary specimen. When fewer than six are currently available, either add them to an established compatible group with known lineage management or wait until a responsible social plan is possible.

Species Identity and the Two Scientific Names

The name used for this product

This catalogue uses Skiffia bilineata, the accepted combination shown by FishBase and our stock records. The species belongs to order Cyprinodontiformes and family Goodeidae, whose members are commonly called splitfins. It is a goodeid livebearer, not a guppy, platy or molly from family Poeciliidae.

Where Neotoca bilineata fits

The former or alternative specialist name Neotoca bilineata appears in older aquarium literature and remains in use by the Goodeid Working Group. ITIS records that name as a synonym, while specialist phylogenetic interpretation may recognise Neotoca separately. These labels refer to the same product identity here; they do not describe two sale options or justify repeating both names throughout the page.

Name or group	How it is used here	Customer consequence
Skiffia bilineata	Primary catalogue name	Used in the title and care data
Neotoca bilineata	Former or alternative specialist name	Useful for recognising older references
Twoline Skiffia	Established English common name	Used naturally for customer recognition
Goodeidae	Family	Explains splitfin and livebearing biology
Goodeinae	Subfamily	Males develop the characteristic split anal fin

Natural range

The species is endemic to west-central Mexico. Published records place it in systems associated with the Lerma basin, Lake Cuitzeo and parts of the Rio Grande de Santiago drainage. Its habitats include quiet or slow-moving, often shallow water with vegetation, mud, silt, sand, rock and organic material. This product has no named wild locality, so the listing does not attach it to a particular river, lake or conservation population.

Care at a Glance

Care point	Practical recommendation
Scientific name	Skiffia bilineata
Alternative name	Neotoca bilineata
Family	Goodeidae
Supplied size	Approximately 2-3 cm
Adult planning size	Up to about 6 cm total length
Minimum same-species group	Six
Practical minimum aquarium	80L+, at least 60 cm long for six
Preferred long-term temperature	18-24°C
pH	7.0-7.5
Hardness	Approximately 5-20 dGH
Diet	Micro-omnivore; complete staple plus small invertebrate and grazing foods
Temperament	Active and social; display and pursuit require structure
Tank region	Lower to middle water, using planted margins and open feeding areas
Care level	Moderate to advanced

Is This Fish Right for Your Aquarium?

A good match when

This species suits a mature, well-covered aquarium with stable neutral-to-mildly alkaline water, moderate hardness, a cooler tropical or temperate-tropical temperature plan and room for a social group. It is especially rewarding for an aquarist interested in goodeids, natural behaviour and careful record keeping rather than a single brightly coloured centrepiece.

Choose another species when

Do not choose it for an uncycled aquarium, a permanently hot discus-style system, a tiny container, or a community built around slow delicate fish. It is also a poor fit when only one individual can be housed, when sex selection is essential, or when a named conservation lineage is required. The product does not include population provenance.

Existing setup	Suitability	Why
Mature 80L+ planted aquarium	Potentially suitable	Confirm length, group number and water
Cooler livebearer display	Potentially suitable	Use compatible species and prevent lineage confusion
28-30°C warm-water community	Unsuitable long term	Continuous heat is outside the preferred plan
30L nano aquarium	Unsuitable	Insufficient space for a stable group
Single-fish display	Unsuitable	The species should be kept socially
Named-population breeding project	Not supported by this listing	No population code or lineage is documented
Uncycled new aquarium	Unsuitable	Ammonia and nitrite must remain at zero

Why care is not labelled easy

The fish is small and accepts prepared food, but responsible care asks more than basic feeding. A keeper must manage a complete group, avoid chronic heat, maintain moderately hard stable water, recognise social pressure and avoid casual mixing that could compromise goodeid identity. Those requirements make a moderate-to-advanced label more honest than marketing it as an effortless beginner livebearer.

Aquarium Size and Group Footprint

Practical minimum for six

Use at least 80 litres with 60 cm or more aquarium length for six adults. The Goodeid Working Group gives 60 litres as a species minimum; the larger working recommendation provides more room for plant cover, visual barriers, feeding access and water-quality stability. A larger aquarium is appropriate for more fish, substantial companions or a keeper who wants a self-sustaining colony.

Length and structure matter

A tall tank can hold the same litres as a longer one while offering less useful territory. This species uses shallow, structured habitats in nature and benefits from horizontal room divided by vegetation, wood and smooth stone. Leave open areas for group feeding and observation, but prevent one fish from seeing every other fish across a completely bare box.

Planning case	Direction	Important note
Six adults, species-led setup	80L+, 60 cm length	Use dense refuge and open feeding space
Larger colony	Increase length and volume	Watch social balance and filtration load
Group with tank mates	Increase footprint	Fit every species at its full group size
Juvenile holding arrangement	Short and planned only	Do not delay the adult setup indefinitely
Breeding or lineage project	Dedicated aquarium preferred	Keep records and avoid species mixing

A secure cover

Fit a close cover and check the gaps around hoses, cables and feeders. Active livebearers can jump when startled or pursued. A lid should prevent escape without suppressing normal gas exchange. Recheck it after every maintenance session; a shifted panel or forgotten feeding hatch can undo an otherwise careful setup.

Temperature and Seasonal Management

Everyday target

A stable 18-24°C is a practical long-term range for most home setups. The fish can occur across broader conditions, but the goal is not to test the edge of tolerance. Avoid placing the aquarium beside a radiator or in direct summer sun. Use a reliable thermometer, and plan cooling or room ventilation before a heatwave rather than after fish show respiratory stress.

Avoid continuous high heat

The specialist account warns that holding this goodeid continuously above 24°C can reduce resistance and accelerate ageing. A brief warm period is not the same as permanent heat, but a tank that sits at 26-28°C all year should be assigned to a genuinely warm-water species. At higher temperature, oxygen demand rises while dissolved oxygen availability falls.

Temperature situation	Meaning	Action
18-22°C	Comfortable routine range	Keep stable with good oxygenation
22-24°C	Warmer routine range	Observe oxygen and avoid crowding
Above 24°C continuously	Poor long-term plan	Reduce room heat safely or choose another species
16-19°C planned winter phase	Advanced seasonal option	Use only for an established healthy group and change gradually
Sudden multi-degree shift	Stress risk	Correct the cause gradually unless an emergency requires action

Optional winter rest

Experienced keepers may provide an established group with two to three cooler months below 20°C, often around 16-19°C, to reflect seasonal husbandry and give a reproductive pause. This is optional advanced management, not an arrival-day instruction. Never move a newly delivered juvenile abruptly into cold water, and do not create a seasonal change without confirming that tank mates share the same needs.

Water Parameters and Stability

Target pH 7.0-7.5 and approximately 5-20 dGH. This is a neutral to mildly alkaline, moderately hard-water plan. Avoid chasing an exact decimal with repeated chemical corrections. A stable pH of 7.2 is more useful than water that swings between 7.0 and 7.5 because additives are being used to force a number.

Parameter	Target	Management priority
Temperature	18-24°C long term	Avoid chronic heat and sudden change
pH	7.0-7.5	Stability before precision
General hardness	About 5-20 dGH	Maintain minerals consistently
Ammonia	0	Any detectable reading needs immediate investigation
Nitrite	0	Any detectable reading needs immediate investigation
Nitrate	Low and stable	Control through stocking, feeding and water changes

Test the water you actually have

Measure the aquarium and tap or prepared source water before ordering. The water matcher can help compare your measured conditions with the intended range. Where the tap supply is very soft, use a repeatable remineralisation method rather than adding an unmeasured amount of mineral product. Where it is extremely hard or alkaline, choose a suitable dilution plan or a fish that naturally matches the water.

Acclimation cannot fix an unsuitable system

Slow introduction reduces the stress of a difference between transport water and aquarium water, but it does not make an unsuitable long-term chemistry safe. Prepare the destination first. Ammonia and nitrite must remain at zero, temperature must be stable, and the biological filter must already be mature enough for the planned group.

Filtration, Flow and Oxygen

Mature biological capacity

Use a cycled filter with enough biological media for the adult group and any companions. Small fish still produce a meaningful combined load when kept as six or more, particularly when powdered, frozen or live foods are offered. Choose equipment that is easy to inspect and clean so maintenance is performed before flow declines.

Gentle to moderate movement

Natural habitat descriptions include quiet water and slight current, so the aquarium does not need a forceful river jet. Distribute the return so the surface moves and oxygen enters without pinning fish against one end. Plants and wood can create calmer pockets. Guard intakes where a 2-3 cm juvenile could be trapped or repeatedly pulled toward a grille.

Oxygen during warm weather

Surface movement matters most when the room is warm, the group is active or medication reduces oxygen. Rapid breathing across several fish, gathering at the surface or loss of coordination calls for immediate checks of temperature, ammonia, nitrite, filter operation and gas exchange. Do not assume that adding an air stone solves the underlying water-quality fault.

Aquascaping a Useful Habitat

Build the layout around cover, visibility breaks and clean feeding access. Dense planting at the back and sides can shelter juveniles and allow a pursued fish to leave view. Smooth wood, small branches, rounded stones and a little leaf litter can add structure. Keep enough open substrate or midwater space to observe every fish at feeding time.

Aquarium zone	Purpose	Avoid
Back and side margins	Dense plants and visual refuge	A bare line of sight across the entire tank
Centre	Open group movement and feeding	A cramped hardscape maze
Lower level	Smooth substrate, leaves and low cover	Sharp gravel or waste-trapping pockets
Surface	Gas exchange, shade and secure cover	Blocked flow or escape gaps
Filter area	Reliable circulation and protected intake	Unscreened suction near juveniles

Plants and grazing surfaces

Fine-leaved and bushy plants provide useful refuge, while older wood and stone can support biofilm and aufwuchs. Do not sterilise every surface until it is visually bare. At the same time, remove decaying material before it compromises water. If live plants repeatedly fail under the chosen hardness or temperature, use safe artificial cover rather than leaving the group exposed.

Lighting

Moderate light with shaded areas usually allows natural observation without making the fish feel exposed. Switch room light on before a sudden aquarium light, or use a timed ramp where available. Fish arriving after transport may look pale and hide initially; strong light and repeated disturbance will not make adult colour appear faster.

Social Behaviour and Group Dynamics

Keep at least six

A group spreads social attention and gives individuals several choices of companion and refuge. A singleton cannot show normal group interaction, while a pair can concentrate pursuit on one fish. Six is a practical starting point, not a magical maximum. Increase the aquarium footprint, filtration and cover for a larger colony.

Display is not automatically aggression

Adult males can develop dark fins and stronger colour during courtship or social display. Brief chasing may occur, especially when fish mature. The important distinction is whether every individual continues to feed, rest and use the tank normally. Repeated cornering, damaged fins, weight loss or one fish staying hidden throughout the day signals a management problem.

Use structure before adding more fish

When tension appears, first check aquarium size, group composition, cover, water quality and feeding distribution. Rearranging sight lines can be more useful than automatically adding livestock. Any new fish changes the social system and biological load. A divider or separate mature aquarium may be required if one individual remains under sustained pressure.

Tank Mates and Compatibility

A species-focused aquarium is the simplest option. In a community, choose calm fish of similar size that accept the same 18-24°C, neutral-to-mildly alkaline, moderately hard water. Match feeding speed and adult behaviour, not just current length. Avoid predators, persistent fin-nippers and warm-water-only species.

Companion type	Assessment	Reason
Calm similarly sized hard-water fish	Often possible	Confirm full adult group and temperature overlap
Peaceful bottom dwellers	Possible with care	Protect feeding access and floor space
Slow long-finned fish	Use caution or avoid	Activity and pursuit may cause stress
Aggressive fin-nippers	Avoid	Risk of injury and chronic pressure
Large predatory fish	Avoid	The goodeid may be swallowed or harassed
Fish needing 27-30°C	Avoid long term	Temperature needs conflict
Other goodeid species	Dedicated management preferred	Prevent hybridisation and lineage confusion
Dwarf shrimp and newborn fry	At risk	Small moving animals may be eaten

Why a general livebearer label is not enough

Many shop categories place goodeids beside guppies, mollies and platies, but those fish do not all share identical temperature, salinity, hardness or social needs. Use the livebearer hub to compare options, then return to the species-level requirements. Similar reproductive biology does not guarantee community compatibility.

Rare-fish planning

The rare and collector fish hub can help compare unusual alternatives. Rarity should never replace welfare as the reason to buy. Choose this fish only when its group, temperature and water requirements already fit; do not use an endangered status or uncommon name as permission for an unsuitable impulse purchase.

Feeding a Micro-Omnivore

Use a complete staple

Base the diet on a quality small flake, soft granule or appropriately sized micro-pellet that provides complete nutrition. Rotate suitable formats so all individuals can feed. Crush food only as much as needed for the 2-3 cm supplied size; excessive dust disappears into the substrate and increases waste.

Add small invertebrate foods

The specialist profile describes tiny invertebrates, insect larvae, aufwuchs and detritus in the natural diet. Small frozen or live foods such as daphnia, cyclops and brine-shrimp nauplii can provide variety. Use clean, aquarium-safe sources and keep portions modest. A varied diet is useful; a rich meat-only diet is not.

Encourage natural browsing

Mature surfaces, biofilm and fine plant structure support picking behaviour between meals. This does not replace a nutritionally complete diet. Avoid introducing objects from outdoor water without a safe preparation method, because parasites, pollutants and unwanted organisms can accompany them.

Food type	Role	Use
Quality micro-pellet, granule or flake	Complete staple	Small portions once or twice daily
Daphnia or cyclops	Small invertebrate variety	Rotate in modest portions
Brine-shrimp nauplii	Useful small live/frozen food	Appropriate for juveniles and adults
Freeze-dried foods	Occasional variety	Pre-soak where appropriate and avoid excess
Biofilm and aufwuchs	Browsing opportunity	Support with mature safe surfaces
Large hard pellets	Poor match	May be inaccessible at the supplied size
High-fat meat-only diet	Unsuitable routine	Does not reflect the varied natural feeding pattern

Feed the whole group, not the fastest fish

Distribute food across two or more points and watch each individual take it. A fish that repeatedly misses meals may be socially excluded, unwell or unable to handle the food size. Remove obvious leftovers. Adjust quantity from body condition, feeding response and water tests rather than adding food simply because fish continue to approach the glass.

A Practical Maintenance Routine

Daily observation

Count the group, compare breathing, check that every fish feeds and confirm normal filter return. Look for fin damage, clamped posture, white spots, stringy waste, swelling or one fish isolating. A brief consistent observation catches change earlier than occasional disruptive handling.

Weekly work guided by tests

Test nitrate and any unstable parameter, remove trapped food and plant debris, inspect intake guards and perform an appropriate partial water change. Match replacement-water temperature and mineral content. The specialist profile describes modest regular water changes as sufficient under suitable stocking, but the aquarium's measured nitrate and feeding load should determine the actual schedule.

Monthly system review

Inspect hoses, seals, impellers, lid gaps, heater or room-temperature control and hardscape stability. Review whether the group has outgrown its visual barriers or filtration. Rinse mechanical media as required and protect biological media from chlorine and unnecessary complete replacement.

Interval	Core checks	Purpose
Daily	Count, breathing, feeding, flow, social pressure	Detect change early
Weekly	Water tests, partial change, debris removal	Control waste and verify stability
Monthly	Equipment, cover, media, hardscape, group condition	Prevent gradual mechanical or space problems
During hot weather	Temperature, oxygen, room ventilation	Avoid chronic heat and respiratory stress
After adding livestock	Ammonia, nitrite, feeding access, behaviour	Confirm the system absorbed the new load

Preparing for Arrival and Acclimation

Before dispatch

The aquarium should be fully cycled, covered, at a stable temperature and within the planned pH and hardness range. Prepare a dim refuge and confirm that filter intakes are safe for a 2-3 cm fish. Do not order livestock while a new tank is still producing ammonia or nitrite, during a known household move, or when nobody can receive the delivery.

On delivery day

Open the outer box in a calm room and follow the current instructions supplied with the order. Keep the aquarium light low. Compare transport and tank conditions rather than using a fixed ritual for every delivery. The acclimation timer can support the process, but observation and the included livestock instructions take priority.

Do not pour transport water into the aquarium

Transfer the fish with appropriate equipment after the instructed acclimation method and discard transport water. Avoid chasing a small fish around a large bucket. Once introduced, leave the group to settle. Do not repeatedly lift decor, tap the glass or add food every hour in an attempt to force a response.

The first evening

Paler colour, cautious movement and reduced appetite can follow transport. Check breathing and balance, keep disturbance low and offer only a small amount of familiar-sized food if the fish is settled. Remove leftovers. A fish that cannot remain upright, gasps persistently or shows a rapid worsening pattern needs prompt investigation rather than passive waiting.

Appearance, Development and Gallery Disclosure

Natural appearance

Adults are generally silver-grey with darker patterning. Males may develop darker dorsal and anal fins and stronger yellow-black flank contrast during display, while females are often larger and can remain more subdued. Lighting, substrate, age, social condition and stress affect how visible these features are. A juvenile may not resemble a fully displaying adult.

No colour or sex guarantee

The supplied fish is approximately 2-3 cm and unsexed. The listing does not promise a specific fin colour, stripe count, body depth, reproductive state or adult sex. Those traits develop and vary. A fish looking pale in the bag is not proof of the wrong species, and a dark individual is not automatically male without the relevant mature anal-fin structure.

About the four images

All four images are representative illustrations intended to communicate the general fish and aquarium context; none is an exact-stock photograph. The old files include the word `female`, but filenames are not a purchase option and do not override the current unsexed sale contract.

Sexing and Reproduction

How mature fish differ

Mature males develop the split anal-fin arrangement characteristic of goodeine fishes and are generally smaller and more slender. Females can grow larger and may show a fuller body. At the juvenile supplied size, reliable sexing is not promised. Do not interpret one still image or a temporary colour change as a guaranteed sex.

A different kind of livebearer

Goodeids give birth to live young, but their reproductive biology differs from the familiar poeciliid pattern of guppies and platies. Developing young receive maternal support through specialised trophotaeniae. This is useful biological context, not a guarantee that a newly purchased group will breed or that fry will survive.

If breeding occurs

Dense fine cover can help fry avoid disturbance, and adults may not always consume them when food and refuge are adequate. Watch that smaller fish can feed. A dedicated grow-out arrangement may still be necessary. Keep accurate dates, parent information and source records if the aim is more than a casual home colony.

Do not assign a conservation lineage

Responsible goodeid breeding depends on knowing the source population. This product has no documented ESU, river, lake or captive population code, so offspring should not be labelled as a named conservation line. Avoid mixing it with another goodeid where hybridisation or later identification could become uncertain.

Conservation Context Without Sales Claims

The IUCN Red List assessment classifies the species as Endangered. Habitat modification, pollution, introduced species and local population loss are part of its documented context. That status deserves accurate language: the species is not globally classified as Extinct in the Wild.

Some historic geographic populations appear to have disappeared while others persist. The Goodeid Working Group profile gives a detailed account of distribution, habitat and husbandry under the alternative genus. These sources support education, but they do not establish the provenance of the individual offered here.

Welfare Checks and Signs of Trouble

Normal settling behaviour

A newly arrived juvenile may shelter, carry muted colour and eat cautiously. Improvement should be gradual: breathing steadies, the fish joins the group, fins open and appetite returns. Compare individuals rather than judging one moment. A consistent daily note or photograph can reveal whether condition is improving without repeated handling.

Signals requiring investigation

Persistent rapid breathing, gasping, loss of balance, clamped fins, repeated rubbing, visible spots, ulcers, severe swelling, ongoing white/stringy waste, progressive weight loss or social exclusion are not normal variations. Test water immediately. Check temperature, filter flow and oxygen before assuming a pathogen. Seek qualified aquatic veterinary advice where symptoms are severe, spreading or unexplained.

Observation	First checks	Avoid
Whole group breathing rapidly	Temperature, oxygen, ammonia, nitrite, filter	Blindly adding medication
One fish always hiding	Pursuit, cover, injury, feeding access	Assuming it is simply shy forever
Loss of appetite	Water, food size, social pressure, visible disease	Adding larger portions that decay
Fin damage	Tank mates, displays, sharp decor, water quality	Treating without removing the cause
Repeated surface gathering	Oxygen, heat, toxins, flow	Waiting for the next routine water change
Gradual weight loss	Individual feeding, parasites, chronic stress	Overfeeding the entire aquarium

Medication caution

Do not combine treatments or dose a display tank on guesswork. Confirm the active ingredient, calculate the real water volume and consider the sensitivity of plants, invertebrates and biological filtration. Quarantine is most useful when it is a mature, appropriately sized system with stable conditions, not an uncycled container created after a problem appears.

Common Setup Problems

The aquarium keeps reaching 26-28°C

Check room heat, sunlight, enclosed cabinets, pump heat and an incorrectly set heater. Improve safe ventilation and surface movement. Any temperature reduction should be controlled; a sudden large drop can be as stressful as the heat. If the home cannot maintain a suitable long-term range, choose another species rather than relying on permanent emergency cooling.

One individual is pursued

Confirm the group is large enough and the aquarium provides genuine sight breaks. Add or rearrange safe cover, spread feeding points and monitor for injury. A persistent aggressor or weakened target may need separation into another mature system. Do not add random fish until water capacity and likely social effects have been assessed.

Prepared food is ignored

Check food size and whether faster fish take everything. Offer a small familiar live or frozen food to establish feeding, then transition gradually to a complete staple. Maintain hygiene and remove leftovers. Persistent refusal accompanied by rapid breathing, weight loss or isolation points to a welfare problem rather than simple preference.

pH falls between water changes

Measure KH, source-water chemistry, stocking, organic waste and the interval between changes. Low buffering combined with biological acid production can drive a decline. Correct the maintenance and mineral plan consistently. Avoid a large one-off alkaline dose that causes a rapid swing.

A Responsible First-Month Plan

Period	Main task	What success looks like
Before arrival	Cycle, test, cover and stabilise the aquarium	Zero ammonia/nitrite and matching water
First 24 hours	Low disturbance and close breathing checks	Balanced swimming and gradual settling
Days 2-7	Confirm every fish feeds and monitor water daily	No exclusion and stable test results
Week 2	Review cover, feeding points and maintenance load	Group uses the full habitat calmly
Weeks 3-4	Assess body condition and long-term temperature	Even growth, normal fins and reliable routine
After one month	Decide whether any community additions are justified	Existing group remains the priority

Delay new tank mates until the current group is feeding reliably and the filter has demonstrated stable capacity. A visually quiet first week is not an empty space that must be filled. Small juveniles grow, mature and establish social relationships; let the aquarium reveal its real load before making another livestock decision.

Ordering and UK Delivery

Check availability and quantity

The page reflects the current Shopify inventory. When out of stock, do not substitute an unsuitable species solely because the aquarium is ready. When available, quantity one is one unsexed fish. Build or extend a group only when the aquarium has the space, filtration and social plan for every individual.

First-order offer

Eligible first-time customers can use WELCOME10 for 10% off under the current promotion terms. The discount does not change the livestock quantity, sex or care requirements. Check the basket and current terms before payment rather than treating promotional text as a permanent price promise.

Delivery protection

Eligible livestock delivery is covered by the Live Arrival Guarantee. Read the current delivery and guarantee information before ordering because dispatch days, postcode coverage, evidence requirements and exclusions can change. Arrange for someone to receive the parcel and have the destination aquarium ready before the delivery window.

Browse the correct category

The Skiffia category contains related catalogue options. Similar trade names can refer to different species, so compare the scientific name, adult size, temperature and sale unit on each page. Do not assume that every spotted or splitfin goodeid has the same care or lineage.

Frequently Asked Questions

How many fish are included?

One live fish is included per quantity selected. The approximate supplied size is 2-3 cm. A new social setup should plan for at least six of the same species.

Is the fish guaranteed to be female?

No. Our stock records and Shopify option do not specify sex, so the fish is sold as unsexed. The old URL and media filenames contain historic female wording but do not create a current sex guarantee.

Why do I see both Skiffia bilineata and Neotoca bilineata?

They are taxonomic treatments of the same species identity here. This product uses Skiffia bilineata as the primary current name, while Neotoca bilineata helps customers recognise older and specialist literature.

How large does it grow?

Plan for up to about 6 cm total length, allowing for larger adult females. Supplied juveniles at 2-3 cm are not close to their complete adult footprint or social development.

What minimum aquarium is suitable?

For six, use at least 80 litres and 60 cm aquarium length. Increase the footprint for a larger colony or tank mates. Dense refuge and open feeding space both matter.

Can I keep one Twoline Skiffia?

A permanent singleton is not recommended. Keep at least six so social attention is distributed and normal group behaviour is possible.

Does it need a heater?

That depends on the room. The long-term target is 18-24°C, so a cool stable home may not need continuous heating. Use a reliable thermometer and protect the aquarium from sudden drops or summer overheating.

What pH and hardness are best?

Target pH 7.0-7.5 and approximately 5-20 dGH with stable chemistry, zero ammonia and zero nitrite. Test the aquarium rather than relying on a regional tap-water assumption.

What should I feed it?

Use a quality complete micro-pellet, granule or flake as the staple, with varied small frozen or live invertebrate foods and safe mature surfaces for grazing. Keep portions small enough that waste does not accumulate.

Can it live with guppies or other livebearers?

Only when adult size, temperature, hardness, behaviour and lineage management all match. The shared label `livebearer` is not enough. Avoid mixing goodeid species where hybridisation or later identification could become uncertain.

Is the species extinct in the wild?

No. The global IUCN category is Endangered. Some historical populations may be lost, while surviving populations remain documented. This product has no named population provenance or conservation-programme claim.

Are the gallery images the exact fish I will receive?

No. All four are representative illustrations. Exact colour, pattern, body shape, maturity and sex vary between live individuals, and the gallery is not a set of exact-stock photographs.

Evidence and Editorial Method

Identity, size, broad water records and global conservation status were checked against FishBase. Taxonomic context was cross-checked with NCBI Taxonomy and ITIS. Habitat, diet, temperature management and aquarium recommendations were informed by the Goodeid Working Group's specialist profile. The practical 80-litre group recommendation deliberately adds working room above that profile's 60-litre minimum.

Scientific sources describe populations and biological limits; they do not automatically prescribe every detail of a home aquarium. Where this page gives a practical recommendation, it is labelled as such and chosen conservatively. The text does not invent a sex, locality, lineage, review score, exact-stock image, breeding guarantee, quarantine process or conservation donation.