Xiphophorus helleri mary gold ada

Choose this swordtail for space, colour and active behaviour

The Mary Gold Ada swordtail (Xiphophorus helleri) is an ornamental freshwater livebearer in the family Poeciliidae. The species is native to North and Central America, from Veracruz in Mexico to north-western Honduras, and reaches 14 cm. It suits a keeper who can provide a long, filtered aquarium, neutral-to-alkaline water and carefully screened companions. Its adult size and active swimming needs make it a deliberate community-aquarium choice rather than a fish for a compact tank.

FishBase describes the species as occurring in freshwater and brackish environments. FishBase now lists it as Xiphophorus hellerii. It belongs to the same livebearing family as platies and other poeciliids; you can compare their different space and social needs in our livebearers collection.

Understand the wild fish before planning the aquarium

Wild adults occur mainly in rapidly flowing streams and rivers with heavy vegetation. They are also associated with warm springs, weedy canals and ponds. That combination points to a practical aquarium layout: preserve an open swimming route, add substantial plant cover and provide some water movement without turning the whole aquarium into a high-flow channel.

The recorded wild diet includes worms, crustaceans, insects and plant matter. Seriously Fish further describes a generalised omnivore that consumes aquatic and terrestrial invertebrates, organic detritus, algae and other plant material. Aquarium feeding should therefore combine a good dried staple with suitable small live or frozen foods instead of relying on one ingredient.

Plan around the decisive figures

• Adult size: 14 cm.
• Smallest aquarium to consider: about 108 litres with a 120 × 30 cm base or an equivalent footprint.
• Routine water: 22–27°C, pH 7.0–8.0 and 10–12 dGH.
• Social plan: OATA suggests at least three swordtails, with two females to each male in a known mixed-sex group.
• Main behavioural concern: males can be aggressive towards one another, while large swordtails may be boisterous with timid companions.

These figures work together. A suitable volume without the necessary swimming length is not enough, and matching the temperature while ignoring pH or hardness does not create a complete water match. Start with the adult footprint, check all three routine water values and then assess the proposed social group.

Match the individual offer to your aquarium plan

This fish is sold individually, with one purchase supplying one animal. The dispatch grade is 4–5 cm; that grade describes the fish at dispatch, not its 14 cm adult size. Build the permanent aquarium around the adult fish from the outset rather than treating the arrival length as a guide to long-term space.

Sex is guaranteed only when the selected option explicitly states male or female. This Xiphophorus helleri mary gold ada listing has no sex-guaranteed option. Use the offer as one unsexed swordtail in your planning and do not infer sex from colour, apparent fin shape or the gallery.

The gallery images are representative of this type of animal rather than photographs of the exact animal supplied, so colours can look slightly different from the live animal. The pictured golden-orange body and elongated lower tail ray show the appearance of the form represented in the gallery, but the photograph does not change the sold unit or establish the sex of the fish.

Decide whether the match is right

OATA's platy and swordtail guidance suggests that at least three are kept together, using two females to each male in a known mixed-sex group. This is group-level planning for swordtails rather than a rule established for this ornamental form. More fish require more aquarium volume, and male aggression means the number alone cannot replace observation of the group.

For a first aquarium, confirm the footprint, mature the filter and test the water before deciding on livestock. For an established aquarium, count every existing fish against the space and filtration capacity rather than checking only whether the new swordtail can physically enter the tank.

Plan the aquarium around the 14 cm adult size

Use 14 cm as the adult planning size. Seriously Fish records 140 mm standard length and says an aquarium with a 120 × 30 cm base, or an equivalent footprint, should be the smallest considered. Its approximate volume is 108 litres. FishBase also records a maximum length of 14 cm and describes a minimum aquarium length of 80 cm, but the larger 120 × 30 cm footprint provides the decisive species husbandry benchmark used here.

Prioritise footprint before nominal volume

Volume helps dilute waste and stabilise temperature, but the base dimensions determine whether a fish has a useful swimming route. Start with a base of at least 120 × 30 cm. An unusually tall aquarium that reaches 108 litres without an equivalent horizontal footprint does not meet the same swimming-space decision. Measure the base directly rather than relying on a marketing name such as small, medium or large.

Preserve a clear route through the aquarium when adding plants, wood and ornaments. A heavily planted setting is suitable, but cover should frame the swimming area rather than fill every open section. Check the completed layout from end to end: the fish should have cover to move into and a continuous route away from that cover.

Allow for the whole population

The 108-litre figure is the smallest aquarium to consider for the species, not a promise that every possible group or community will fit. OATA advises that more groups require a larger volume. Count the adult sizes of all residents, consider the group of swordtails you intend to keep and leave enough room for the filter and layout to function without crowding.

A worked example makes the distinction clear. A 120 × 30 cm aquarium of about 108 litres meets the starting footprint for this swordtail, but adding several other active fish can still make the final population unsuitable. Conversely, a tank with a large nominal volume but a base shorter than 120 cm misses the species profile's minimum horizontal dimension. Both footprint and total stocking therefore need to pass.

Recheck the plan as the fish grows

Do not wait for the fish to approach 14 cm before providing its permanent space. Growth increases waste production and changes how much room remains between companions. Review the swimming route, chasing behaviour and filtration performance as part of normal care. If plants or décor have reduced the usable footprint, thin or reposition them while retaining cover.

Judge companion space by adult measurements as well. The aquarium must accommodate the swordtail at 14 cm together with the mature sizes and behaviour of every other resident; the small size of a new arrival is not a safe basis for permanent stocking.

Keep the routine water inside the shared range

Keep this swordtail at 22–27°C, pH 7.0–8.0 and 10–12 dGH. These routine figures are the overlap of FishBase's recorded environment, the Seriously Fish aquarium range and OATA's swordtail guidance; OATA's figures are broad group guidance, not a species-specific optimum. The overlap gives one coherent target that remains inside every named range.

Temperature, pH and hardness are separate decisions. A reading of 24°C passes the temperature check, but the aquarium still needs pH between 7.0 and 8.0 and general hardness between 10 and 12 dGH. Use actual test results rather than assuming that clear water or a steady temperature means the chemistry also matches.

Read the range as boundaries

The narrow hardness overlap deserves an actual test. If your aquarium measures 11 dGH, it sits inside the routine range. A result of 6 dGH or 18 dGH does not. Use our water chemistry guide to understand each measurement, then compare your readings with the stated targets through the water matcher.

Choose stability within the range

A larger aquarium is easier to keep environmentally stable than a smaller one. Select a temperature within 22–27°C that you can hold consistently, then confirm that the intended companions share it. Apply the same test to pH and hardness; passing one figure does not compensate for missing another.

Test the actual aquarium before adding fish. Ammonia and nitrite must both read zero because either indicates that biological filtration is not processing waste safely. Nitrate is managed as a relative figure: it should not rise more than 20 mg per litre above the normal level in your tap water.

Record results so that a change is visible rather than guessed. A single reading shows the condition at that moment, while regular results reveal whether feeding, stocking or filter performance is moving the aquarium away from its target. When a reading is outside the range, correct the aquarium plan before adding livestock instead of expecting the fish to bridge the mismatch.

Establish biological filtration before adding the fish

Use a well-established, maintained filter from the first day. The RSPCA explains that aquarium filters are vital because fish release toxic ammonia. Beneficial bacteria in a working biological filter convert ammonia to nitrite, which is also toxic, and then to the safer nitrate. The filter is therefore part of the animal's life-support system rather than an optional water-polishing accessory.

Size the filter for the aquarium

For an aquarium of about 108 litres, Seriously Fish uses a turnover of four to five times the aquarium volume per hour and points to a filter rated around 430–540 litres per hour. Treat the rating as a selection guide and arrange the outlet so that the fish receives some water movement without making the whole aquarium excessively turbulent.

Filtration does not need to be particularly strong for this species, although a degree of movement is appreciated. Look at the completed aquarium rather than the rating alone: plants, wood, filter media and blockages can influence how water moves through the layout. Keep an open route while allowing calmer planted areas.

Mature the system before stocking

Prepare the aquarium and establish its biological filter before the swordtail arrives. OATA warns that adding fish too quickly can create new tank syndrome because the bacterial population has not increased enough to process the additional waste. Ammonia and nitrite can then reach unhealthy levels that may cause illness or death.

Increase the aquarium population slowly so the filter bacteria can respond when waste and feeding increase. Our first tropical aquarium guide explains how to prepare and mature the system before livestock is introduced. Test the aquarium rather than judging maturity from how long it has contained water.

Preserve the beneficial bacteria

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

Keep replacement water conditioned before it enters the aquarium. Filter maintenance should restore flow without stripping away the biological community that processes waste. After cleaning, confirm that the filter is running normally and continue the regular ammonia and nitrite tests.

A mature filter does not cancel the need for sensible stocking or feeding. More fish and excess food both add waste, so the biological load must remain within the capacity of the aquarium and its maintenance routine.

Combine plant cover with an open swimming route

Create a planted aquarium with cover around a clear central or front swimming route. Seriously Fish says décor is not especially critical, but this swordtail tends to look best in a heavily planted setting with a dark substrate. Floating plants and driftwood roots or branches can diffuse the light and add a more natural feel.

Build the layout in layers

• Substrate: use aquarium gravel or sand; a dark substrate suits the planted presentation described for the species.
• Low structure: place wood, water-worn rocks or small boulders where they do not shorten the continuous swimming route.
• Plant cover: use live plants where practical. OATA also permits plastic plants and suitable ornaments when live plants are not used.
• Upper cover: add some floating plants if they can be kept clear of the filter intake and the main open-water route.
• Open area: preserve enough unobstructed length for an active adult swordtail.

Wild forms occur in rapidly flowing streams and rivers as well as warm springs, weedy canals and ponds. An aquarium does not need to reproduce one location exactly. The useful features are vegetation, some movement, shelter and open space.

Check movement from the fish's perspective

A degree of water movement is suitable, but filtration does not need to be especially strong. Direct the outlet so water circulates through the aquarium without pinning the fish into one area. Plants should move enough to show circulation while still leaving sheltered sections.

Use the 120 × 30 cm minimum base as the boundary for the layout. Décor placed inside that footprint reduces usable room, so avoid building a solid wall of wood or rock across the swimming path. A branch that diffuses light while leaving space around it is more useful than a dense structure that divides the aquarium into cramped sections.

Keep shelter functional

Cover gives fish somewhere to move when interactions become intense. It is most useful when it creates several visual breaks without trapping an individual in a dead end. Arrange plants and wood so a fish can enter and leave from more than one direction.

Inspect the layout whenever plants grow substantially or ornaments are moved. Retain the planted character while restoring the open route if growth has narrowed it. This keeps the aquarium aligned with both the species' association with vegetation and its need for adult swimming space.

Feed a varied omnivorous diet once daily

Feed a good-quality dried food once daily, adding small live or frozen foods for variety. Offer only what the fish can eat within a few minutes. This schedule follows OATA's swordtail guidance, while the food choices reflect the species' recorded omnivorous diet.

FishBase records worms, crustaceans, insects and plant matter in the wild diet. Seriously Fish adds aquatic and terrestrial invertebrates, organic detritus, algae and other plant material. A suitable aquarium routine therefore includes both animal and plant components.

Give each food a clear role

Do not turn the list into a requirement to feed every item together. The decision is simpler: provide one suitable dried staple and rotate small complementary foods so the diet is not restricted to one product. Keep every item appropriately small for the fish to take.

Control the portion by observation

Add a small amount and watch the fish eat. Stop when the portion that can be consumed within a few minutes has been offered. Uneaten food breaks down and releases waste into the water, so more food is not a substitute for variety or condition.

Use the once-daily feeding time as a welfare check. A healthy feeding response gives you a regular point at which to notice reduced intake, loss of interest, unusual swimming or a change in body condition. If one fish is taking most of the food, spread the portion through the swimming area while keeping the total within the few-minute limit.

Link feeding to water quality

Overfeeding increases the work required from the biological filter and can contribute to ammonia, nitrite or nitrate problems. When uneaten food appears, remove it and reduce the next portion rather than adding a second feed to compensate.

A varied diet does not require a large quantity. Quality, appropriate particle size and controlled portions are the priorities. Maintain the same daily schedule while rotating the complementary foods, and judge the fish by feeding response and body condition rather than by how eagerly it approaches the glass.

Use weekly maintenance to protect water quality

At least once every week, change 25% of the aquarium water. Test ammonia and nitrite at least once per week, and keep both at zero mg per litre. This routine removes dissolved and solid waste while checking that the biological filter continues to process the fish's waste safely.

Complete the weekly sequence

1. Test ammonia, nitrite and nitrate before the water change so the results show how the aquarium has performed.
2. Siphon out 25% of the aquarium water and remove solid waste from the gravel or sand.
3. Treat the replacement water with tap-water conditioner to remove chlorine or chloramine before adding it.
4. Check the filter for blockages and confirm normal circulation.
5. If the filter media needs cleaning, rinse it lightly in the removed aquarium water and do not run it under the tap.
6. Return the aquarium to its routine 22–27°C range and record the test results.

Change 25% of the aquarium water at least once every week. Additional maintenance decisions should follow measured water quality and the amount of solid waste rather than replacing the regular weekly change with occasional large interventions.

Watch for changes at feeding time

Look for clear, bright eyes, intact scales and undamaged fins. OATA identifies several changes that can indicate a developing health or water-quality problem: hanging at the surface, sitting on the bottom, erratic swimming, darker or paler colour, increased aggression, unusual hiding, faster or slower gill movement, white spots, fluffy growths, loss of fins or scales, changes in weight or body condition, and reduced interest in food.

Use the fish's normal behaviour as the comparison. A change matters because it can appear before a more obvious decline. Record what changed, when it began and whether more than one fish is affected. This makes the next action more focused than treating every unusual movement as the same problem.

Test before interpreting symptoms

When behaviour, breathing, appearance or appetite changes, test ammonia, nitrite, nitrate, temperature and pH. A zero ammonia result does not remove the need to check nitrite, and a normal temperature does not establish that pH or hardness still matches.

Correct any measurable husbandry problem and contact us if you are concerned about the health of the livestock. Do not begin a disease treatment merely from a colour or behaviour change; use the water results and the full pattern of signs to explain what is happening.

Keep maintenance consistent after the fish appears settled. The filter bacteria, water chemistry and waste load continue to change with feeding, growth and stocking, so weekly testing and partial water changes remain part of long-term care.

Receive, film and acclimatise in the correct order

Have someone at the delivery address to receive the parcel; live fish cannot be left unattended. Open and inspect it on the day it arrives. Before touching the seal, have the aquarium ready within 22–27°C, pH 7.0–8.0 and 10–12 dGH.

Follow the arrival sequence

1. Receive the parcel in person.
2. Start filming while the parcel is still sealed and the outer box is visible.
3. Open the parcel in one continuous take.
4. Show the fish while it is still inside the sealed bag, before anything is disturbed.
5. Float the bag for 20–30 minutes before releasing the fish.
6. Do not pour the bag water into the aquarium.

The fish is hand-bagged in pure oxygen and placed in an insulated poly box, with a heat pack when the weather calls for it. A licensed live-animal courier carries the parcel, and tracking plus the confirmed delivery date are sent by email so someone can be present.

Keep the policy evidence complete

Film every delivery from the sealed parcel onward. For a Live Arrival Guarantee claim, contact us on the day the fish arrives with the order number and continuous unboxing video showing the sealed parcel, the opening and the fish in the sealed bag. Read the current delivery and Live Arrival Guarantee policy before the delivery date.

Once released, compare the fish's breathing, posture and swimming with the health indicators used in routine care. Test the aquarium if behaviour changes. Keep the established filter running and preserve the normal maintenance schedule rather than making unmeasured changes to water chemistry.

Plan the swordtail group before adding companions

OATA suggests keeping at least three platies or swordtails and using two females to each male in a known mixed-sex group. Treat this as swordtail-group guidance and calculate the total adult population before deciding how many the aquarium can hold. More fish require more volume than the starting 108-litre species minimum.

Separate number from behaviour

A group of three is not automatically settled merely because it reaches the suggested number. FishBase states that males are aggressive towards one another. Seriously Fish explains that groups of males in confined spaces tend to form dominance hierarchies and may spend a significant proportion of their time maintaining their positions.

Space therefore matters alongside the ratio. Preserve the 120 × 30 cm minimum footprint, maintain planted cover and leave an open swimming route. If the aquarium already contains other fish, include their adult space requirements before applying the swordtail-group suggestion.

Use ratios only when the sexes are known

The two-females-to-one-male ratio is intended to reduce stress on females or other inhabitants. Apply it only to a group whose sexes can be identified reliably. Adult males possess a gonopodium and are generally smaller than females; the characteristic sword normally occurs in males. Seriously Fish also notes that some ornamental strains can have extended upper tail lobes or other fins, including in females, so an extended fin alone should not carry the whole decision.

Do not build a social plan from the colour shown in the gallery. Colour forms are the result of selective breeding and do not establish the sex or behaviour of an individual fish. Assess the animals themselves and continue to watch the interaction after the group changes.

Anticipate livebearing behaviour

Swordtails are livebearers and give birth to live young. Females can store viable sperm for months, so a female may later produce young even when the immediate group contains no male. Treat that biology as part of population planning rather than as a home-breeding instruction.

Allowing the population to rise without adjusting space and filtration can increase waste faster than the biological filter can process it. Count every fish when assessing the aquarium, increase stocking slowly and continue weekly ammonia and nitrite tests.

Recognise a group that needs reassessment

Repeated chasing, increased aggression, unusual hiding, damaged fins, reduced feeding or a fish persistently sitting away from the group are reasons to review the social plan and water quality. Test the water first, then reassess the number of males, the available adult space and the cover within the layout.

Screen every community companion against the same needs

Choose generally peaceful companions only after confirming that they share 22–27°C, pH 7.0–8.0 and 10–12 dGH and fit the adult space in the aquarium. OATA describes platies and swordtails as generally peaceful and compatible with other species, but also warns that large swordtails can be boisterous and may chase more timid tankmates.

Apply four checks before mixing

Use the narrowest shared water range. For example, a proposed companion that needs pH below 7.0 does not match this swordtail's routine pH of 7.0–8.0. A species that shares the pH but requires water softer than 10 dGH also fails the complete water check.

Treat named behavioural risks as cautions

Groups containing multiple males need particular scrutiny because male aggression and dominance behaviour are documented. Large swordtails also need care around timid companions. These are cautions requiring enough room, cover and observation; they do not establish a universal list of compatible species.

Fin condition is part of the observation check. Male aggression is the documented concern, so look for chasing, hiding, reduced feeding and damaged fins rather than assuming that a broad community-fish description guarantees every interaction.

Assess invertebrates individually

Treat invertebrate compatibility as uncertain. Crustaceans occur in the species' recorded wild diet, but that fact does not establish what an individual swordtail will do with every aquarium invertebrate. Consider the invertebrate's size, behaviour, cover and water requirements, and do not present the pairing as universally safe.

For a stocking assessment, ask us with the aquarium dimensions, volume, temperature, pH, dGH, current residents and intended number of swordtails. Those details allow the proposed combination to be checked as one aquarium rather than as isolated species names.

Use worked checks to make the final stocking decision

Pass the aquarium through space, water, filtration and behaviour checks in that order. A match that fails an early check should not move ahead merely because the fish is generally described as peaceful.

Example: a suitable starting point

An established aquarium measures 120 × 30 cm at the base, holds about 108 litres, runs at 24°C, pH 7.5 and 11 dGH, and tests zero for ammonia and nitrite. Those figures pass the starting space and routine water checks. The keeper must still count existing residents, assess the proposed swordtail group and ensure that timid fish will not be exposed to boisterous chasing.

Example: enough litres but insufficient length

A tall aquarium holds 110 litres but has a base shorter than 120 cm. Its nominal volume exceeds 108 litres, yet it does not meet the 120 × 30 cm footprint described as the smallest to consider. Choose a fish suited to the existing dimensions or use an aquarium with the necessary horizontal space.

Example: a partial water match

An aquarium runs at 25°C and pH 7.4 but measures 6 dGH. The temperature and pH pass, while hardness falls outside the routine 10–12 dGH range. That is not a complete match. Select livestock for the measured water rather than counting two passing values as sufficient.

Example: social pressure after a change

Water remains within range, but one swordtail begins hiding and feeding less while another repeatedly chases it. Review the sex composition where known, the number of males, the open swimming route and the amount of cover. Confirm ammonia and nitrite remain zero because behaviour changes can occur alongside a water-quality problem.

Review the decision as the aquarium changes

Growth, additional livestock, plant growth and heavier feeding can all alter the original calculation. Recheck the usable footprint if the layout becomes dense, and review filtration whenever the population or waste load rises. Keep the 14 cm adult size in the calculation even when the fish is still small.

A sound community plan has no single shortcut. It combines the adult footprint, the full water range, a mature filter, controlled feeding and observation of real interactions. Use those checks consistently rather than relying on colour form, a general temperament word or the size of the fish on arrival.

Answer the key questions before choosing this fish

How big does Xiphophorus helleri mary gold ada get?

It reaches 14 cm as an adult, so plan the aquarium and companions around that figure from the start rather than judging space by a young fish's current length.

What size aquarium does Xiphophorus helleri mary gold ada need?

Use at least about 108 litres with a 120 × 30 cm base or an equivalent footprint. Seriously Fish describes that footprint as the smallest aquarium to consider for the species.

How many Xiphophorus helleri mary gold ada should I keep together?

OATA's swordtail-group guidance suggests at least three, using two females to each male in a known mixed-sex group. More fish require more aquarium volume.

Is Xiphophorus helleri mary gold ada suitable for beginners?

OATA describes most swordtails as undemanding and easy to keep, but this fish still needs a mature filter, at least 108 litres, stable water and a planned social group.

What does Xiphophorus helleri mary gold ada eat?

Feed a good-quality flake or granule with a high algae content once daily, offering only what it eats within a few minutes. Add small Daphnia, Artemia, bloodworm or tubifex for variety.

What temperature and pH does this fish need?

Keep it at 22–27°C, pH 7.0–8.0 and 10–12 dGH, the routine overlap of FishBase, Seriously Fish and OATA swordtail guidance.

Is this swordtail aggressive or likely to nip fins?

Male aggression is the documented concern: males may form dominance hierarchies and chase one another in confined spaces. Monitor chasing, hiding, feeding and fin condition rather than assuming every community interaction will be peaceful.

Which fish or invertebrates can it live with?

Choose generally peaceful species that share 22–27°C, pH 7.0–8.0 and 10–12 dGH. Large swordtails may chase timid fish; assess invertebrates individually because crustaceans occur in the wild diet.

How does this fish arrive alive in the UK?

Start filming the sealed parcel before any bag is floated. Open it in one continuous take, show the fish in the sealed bag, float the bag for 20–30 minutes, then release the fish without pouring bag water into the aquarium.

Read the public references behind the care decisions

• FishBase: Xiphophorus hellerii — accepted identity, family, native distribution, recorded environment, maximum length, wild habitat, diet and male aggression.
• Seriously Fish: Xiphophorus hellerii — aquarium footprint, volume, water ranges, filtration, décor, diet, dimorphism and male hierarchy behaviour.
• OATA: How to look after platies and swordtails — group care, water quality, feeding, maintenance, social planning and health observations.
• RSPCA aquarium environment guidance — biological filtration and the conversion of ammonia through nitrite to nitrate.
• Tropical Fish Co delivery policy — packing, receipt, unboxing video, acclimatisation and Live Arrival Guarantee procedure.