Neon Tetra (Paracheirodon innesi)

Choose the exact offer and plan the group

The Neon Tetra, Paracheirodon innesi, is a small freshwater member of Acestrorhamphidae from the Solimões River drainage in South America. FishBase records a maximum of 2.5 cm standard length. It suits a keeper prepared to maintain a mature, filtered aquarium at least 60 cm long, keep eight or more together and screen every tank mate for peaceful behaviour, shared water needs and predation risk.

Check whether the aquarium fits the fish

One purchase supplies one Neon Tetra in the size chosen through the live selector. This is a single-fish purchase unit rather than a pair, trio or pre-set shoal, so enter the quantity needed for your planned group. The complete group must fit alongside every other adult resident without overloading the aquarium.

Read each size label literally

The size you select is the size supplied, not the adult size. The > 3 cm label does not set an upper measurement, while XL is a size name rather than a centimetre promise. Use the selected fish’s dispatch size when checking whether an established tank mate could swallow it, then use the adult planning references below when judging the long-term community.

Sex is guaranteed only when the selected option explicitly states male or female. This Neon Tetra listing has no sex-guaranteed option.

Some gallery images are representative, based on reference photographs of this species, and none shows the exact animal supplied, so colours can look slightly different from the live animal.

Use the live selector to choose among the listed dispatch sizes. The Neon Tetra collection provides a separate route for comparing related shop entries, while the delivery and Live Arrival Guarantee policy carries the current dispatch terms and reporting steps.

Plan the aquarium around the adult size and social needs

The accepted identity is Paracheirodon innesi, the Neon Tetra. The Catalog of Fishes account places it in Acestrorhamphidae, while its South American distribution includes the Solimões River drainage. The offer identifies these fish as captive-bred; that does not mean they were collected from the native range.

FishBase records a maximum of 2.5 cm standard length. Standard length ends at the base of the tail fin, so it is not interchangeable with a dispatch label or an informal total-length measurement. Seriously Fish gives 30 mm standard length as its aquarium planning reference. Where a few millimetres affect a compatibility decision, plan around the larger 30 mm reference and the actual mouth size of every adult tank mate.

Start with footprint, filtration and group size together

A litre label cannot replace the footprint check. Substrate, wood, internal equipment and other decor reduce usable water, while a short, deep aquarium can carry a similar nominal volume without giving the same horizontal swimming room. Measure the actual base, account for the occupied space and assess the complete adult community rather than converting 60 cm into a universal stocking formula.

Tropical Fish Co uses eight as its conservative starting screen, provided the aquarium can support the whole group. Our retailer assessment is intermediate: routine feeding is manageable, but success depends on mature biological filtration, stable water, appropriate group planning and careful tank-mate selection. Read the complete Neon Tetra care guide when planning the aquarium beyond this product-focused decision page.

Mature the filter before the group arrives

Prepare a biologically mature aquarium before introducing Neon Tetras. The RSPCA explains why a working biological filter is essential: fish waste releases toxic ammonia, bacteria convert it to toxic nitrite and further bacteria convert nitrite to the safer nitrate. Clear-looking water can still contain ammonia or nitrite, so visual clarity never replaces testing.

Use readiness checks rather than a calendar

1. Install and run the aquarium equipment before livestock enters the system.
2. Establish biological filtration for the planned load.
3. Test ammonia and nitrite and require both to read zero.
4. Confirm that temperature remains stable through the normal day and night cycle.
5. Check that the intended group and all adult tank mates fit the usable footprint and filtration capacity.

A fixed number of elapsed weeks does not demonstrate that a filter can process waste. Base the decision on measured water and a filter matured for the intended community. If this is your first setup, follow the first tropical aquarium preparation guide before choosing livestock.

For an aquarium of about 54 litres, Seriously Fish uses a turnover reference of four to five times the aquarium volume each hour, corresponding to a filter rating around 215–270 litres per hour. Treat that as an equipment-planning reference for the stated tank size. Filter ratings are nominal, and media, pipework, head height and maintenance condition can affect working flow.

Arrange the outlet so the aquarium receives circulation without forcing the fish to remain in a high-velocity stream. Smaller tetras benefit from a gentle current, while waste still needs to reach the filter. Observe whether the group can hold position, feed and use the swimming area normally; change the outlet direction or distribution if one forceful jet makes a section unusable.

Do not solve marginal filtration by reducing the shoal below the social plan. Choose an aquarium and filter that can support at least eight fish plus the rest of the adult community. When the existing aquarium is already near its practical limit, revise the whole stocking plan before adding another group.

Hold stable species-appropriate water

Keep Neon Tetras at 21–25°C, pH 5.0–7.0 and 1–2 dGH. These routine values are the overlap of the species-level ranges from Seriously Fish and FishBase: Seriously Fish gives 21–25°C, pH 4.0–7.5 and 1–12 dGH, while FishBase records 20–26°C, pH 5.0–7.0 and 1–2 dH. Favour a stable point shared by every resident rather than moving fish rapidly towards an extreme.

OATA’s tetra and pencilfish sheet gives 22–27°C, pH 6.5–8.0, 4–12 dGH and 3–10 dKH as broad group guidance. Its measurable welfare limits are ammonia at zero, nitrite at zero and nitrate no more than 20 mg per litre above the normal tap-water level. The Neon Tetra values above remain bounded by the two species ranges.

Make water decisions in this order

Learn how the measurements interact through the aquarium water chemistry guide, then enter actual test results in the water matcher. A value printed on a regional water report is useful context, but the aquarium result is the number affecting the fish.

Many UK rooms will not hold 21–25°C consistently throughout the year. Seriously Fish estimates roughly 50 W of heating for an aquarium around 54 litres when the room is near 20°C. Follow the heater maker’s instructions for the actual aquarium volume and room conditions, use a thermostatic aquarium heater where needed and confirm the result with a separate thermometer.

Avoid rapid pH, hardness or temperature correction. First establish the holding conditions, test the destination aquarium and choose a gradual transition that preserves temperature and oxygen. Stability at a suitable shared value is safer than repeatedly chasing a target with large chemical changes.

Arrange cover, light and swimming room

Use the 60 × 30 cm base as a starting footprint, then preserve a clear horizontal route through the aquarium. Place cover around part of the layout instead of filling every part of the swimming area. This gives the group structure to move around while retaining open water for feeding, observation and normal movement.

Build the layout in functional layers

Seriously Fish describes a sandy substrate with driftwood roots and branches as a suitable natural-style arrangement. Dried leaf litter may add cover, and its decomposition supports microbial growth. Replace or remove material as it breaks down in accordance with the aquarium’s maintenance needs; do not let decaying material accumulate beyond the filter and water-change routine.

Aquatic plants suited to dimmer conditions include Microsorum, Taxiphyllum and Cryptocoryne species. Choose plants that also fit the lighting, substrate and maintenance regime of the aquarium. Dimmer areas can be created by the layout without making the entire tank inaccessible for inspection.

Natural peat is unnecessary for this setup, and Seriously Fish advises against it because collecting peat is environmentally damaging and unsustainable. If a natural visual style is wanted, use aquarium-safe wood, leaves or alder cones within a measured maintenance plan rather than relying on peat to force the water towards a number.

Decor must not turn a nominal 54-litre aquarium into a cramped swimming space. After arranging the hardscape, view the tank from above and from the front. If roots, plants or equipment divide the remaining route into short pockets, simplify the layout before calculating the community. A visually full aquascape is not automatically a functionally spacious one.

Feed small complete meals without fouling the water

Use a suitably small complete flake, granule or micro-pellet as the nutritional base. FishBase records wild adults eating worms, small insects, crustaceans and plant matter, while Seriously Fish describes small invertebrates, crustaceans, filamentous algae and fallen fruit. That varied natural diet does not make one frozen item a complete aquarium food.

Add measured variety with appropriately small live or frozen foods. Seriously Fish names chironomid larvae, mosquito larvae, Daphnia and Moina, while OATA also includes small bloodworm and tubifex within its group feeding advice. Match every item to the fish’s mouth and feeding response.

Use one controlled feeding routine

Watch the whole group rather than the quickest fish. Spread a small portion across the feeding area so less assertive individuals have an opportunity to eat. If food repeatedly reaches the substrate untouched, reduce the amount or choose a smaller particle; adding bottom-dwelling fish is not a substitute for portion control.

Uneaten food decomposes and adds waste, increasing the burden on the biological filter. A useful portion is therefore defined by consumption, not by how much the fish initially rush towards. Keep the daily method consistent long enough to judge appetite, then adjust in small steps when group size, food type or feeding behaviour changes.

If one fish stops feeding while the rest continue normally, check its breathing, posture, colour and position in the group, then test the aquarium. Do not hide a persistent appetite change by repeatedly adding richer food. The health section below gives the water-first response for a change that continues.

Introduce the group with a measured transition

Prepare and test the mature aquarium before the fish arrive. Confirm a stable 21–25°C temperature, require ammonia and nitrite to read zero, check the filter and make sure the intended swimming space is clear. Arrival is not the moment to make major changes to decor, filtration or water chemistry.

Follow the arrival sequence

1. Have someone present to receive the parcel because live fish cannot be left unattended.
2. Before opening the parcel, start filming every delivery in one continuous take with the parcel still sealed and the outer box visible.
3. Continue filming while opening the parcel and show the fish still inside the sealed bag before anything is disturbed.
4. Open and inspect the parcel on the same day it arrives.
5. Float the bag for 20–30 minutes before releasing the fish.
6. Never pour the bag water into the aquarium.

Keep the continuous video and order number if a Live Arrival Guarantee claim is needed, and contact us on the day the fish arrive if anything has gone wrong. The policy uses the sealed parcel, continuous opening and fish in the sealed bag to show their condition before release.

After release, observe breathing, posture and swimming. Check that every fish can maintain position and that none is repeatedly driven away from cover or the normal swimming area. Compare individuals with the group instead of treating one brief movement as a diagnosis.

Use first-week checkpoints

• Daily: confirm temperature and inspect breathing, posture, swimming and feeding response.
• After feeding: remove recurring excess and check that quieter fish reach suitably small food.
• After adding the group: test ammonia and nitrite rather than assuming the mature filter has absorbed the extra load.
• If chasing occurs: reassess the tank-mate screen and ensure the group has usable cover and swimming room.

Additions increase both feeding and waste, so the bacterial population must adapt to the changed load. Avoid combining the Neon Tetra group with several unrelated stocking changes on the same day. A controlled introduction makes later water-test or behaviour changes easier to interpret.

Keep maintenance measurable each week

At least once every week, carry out a partial water change of 25%, following OATA’s tetra-group maintenance guidance. Use a siphon to remove settled waste where the layout allows, and treat replacement tap water with a suitable conditioner before it enters the aquarium so chlorine or chloramine does not damage fish or filter bacteria.

Use a repeatable weekly checklist

Test at least weekly and also after a change in stocking, feeding, equipment performance or fish behaviour. Record the results so a gradual rise is visible before it becomes a crisis. A single acceptable reading does not replace an ongoing pattern of stable results.

When filter media needs cleaning, rinse it lightly in water removed from the aquarium during the partial change. Do not run established biological media under the tap because chlorine or chloramine may damage the bacterial population. Clean only as much as needed to restore normal flow rather than stripping every component at once.

Coordinate maintenance with the feeding routine. If uneaten food is repeatedly present, correct the portion instead of relying on a larger water change to compensate. If nitrate rises faster than the established schedule controls it, reassess feeding, stocking, usable volume and maintenance rather than treating the result as an isolated number.

Use the first month to establish a baseline

• Write down the normal temperature at the same time each day.
• Record weekly ammonia, nitrite, nitrate and water-change results.
• Note the usual group position, feeding response and breathing rate.
• Check that filter flow remains consistent after cleaning.
• Review whether every fish can be counted and observed during feeding.

This baseline makes later changes easier to recognise. The aim is not constant adjustment; it is a stable routine that reveals when testing, equipment or stocking needs attention.

Respond to health changes from water outward

Watch for changes in swimming, colour, breathing, temperament, body condition, skin, fins and appetite. Relevant signs include hanging at the surface, sitting on the bottom, erratic swimming, unusual hiding, faster or slower gill movement, white spots, fluffy growths, fin or scale loss and reduced interest in food. A change is a prompt to investigate rather than a diagnosis by itself.

Check the environment before choosing a treatment

1. Confirm temperature with a separate thermometer.
2. Test ammonia and nitrite immediately.
3. Review nitrate, pH and hardness in the context of the aquarium’s normal results.
4. Check filter flow, recent cleaning, new livestock and feeding changes.
5. Compare the affected fish with the rest of the group.
6. Separate incoming or unwell fish safely when professional guidance calls for it.

The RSPCA’s pet-fish health guidance treats altered behaviour and appearance as reasons to check water quality and seek appropriate help. Do not diagnose a named disease from colour loss, isolation or one white mark alone, and do not apply blanket heat, salt or medicine recipes to the whole aquarium from a symptom list.

The MSD Veterinary Manual’s aquarium-fish management reference places water quality and biosecurity at the centre of investigation. Keep test results, the timeline of changes, feeding details and photographs where practical; this gives a professional more useful context than a single symptom.

Contact us for husbandry help when a change follows an introduction, maintenance event or equipment problem. For persistent, severe or rapidly worsening signs, use OATA’s UK fish-vet directory to find suitable veterinary support.

Continue essential filtration and oxygenation while seeking help unless a qualified professional directs otherwise. Avoid making several simultaneous changes, because altering temperature, chemistry, decor and medication together can add stress and make the cause harder to identify.

Screen every tank mate at adult size

Neon Tetras are generally peaceful community fish, but that temperament does not make every combination suitable. OATA advises that small tetras must not be kept with fish large enough to eat them. Apply that rule to the selected dispatch size on arrival and to the adult Neon Tetra over the life of the aquarium.

Seriously Fish describes similarly sized characids, gasteropelecids, lebiasinids, smaller callichthyid or loricariid catfishes and non-predatory small-to-medium cichlids as possible community companions. These are screening categories, not universal approvals. Each candidate still needs compatible water, enough adult space and behaviour suited to a small peaceful shoal.

Run every candidate through the same checks

Avoid fish large enough to swallow a Neon Tetra. Treat persistent chasing, fin-nipping, territorial exclusion and overwhelming food competition as caution signs that require a different plan or separation. Similar body length alone is not enough: body depth, mouth shape, speed and individual behaviour can change the result.

A worked community check starts with the Neon Tetra group of at least eight, then adds the full adult number required by each proposed companion. Allocate footprint, cover, filter capacity and feeding access to all those adults. If the plan only works by keeping several social species in token numbers, simplify it to fewer species with appropriate groups.

Compatibility remains conditional because individual behaviour and aquarium layout vary. Contact us with the aquarium dimensions, usable volume, measured water, filter details, Neon Tetra group size and exact adult identity of every proposed tank mate for a practical stocking and compatibility assessment.

Compare similar fish without assuming a match

Similar trade names and colours do not make two fish interchangeable. Confirm the scientific name before comparing adult size, temperature and group requirements. A visual cue can help narrow an identification, but the final stocking decision must use the named species and its adult needs.

Separate Neon and Cardinal Tetra planning

The FishBase Cardinal Tetra account gives the warmer 23–29°C environmental range and 3 cm maximum standard length used in this comparison. Temperature ranges overlap, but overlap alone does not decide whether the aquarium has enough space, suitable chemistry and proper group sizes for both species.

Very small shrimp, shrimplets, fry and other bite-sized animals require caution. Small crustaceans form part of the Neon Tetra’s natural diet, so do not promise that these animals will be safe in the same aquarium. Dense structure may change encounters, but it does not remove the feeding risk.

Use outcomes rather than labels

• Suitable candidate: peaceful, cannot swallow the tetra, shares stable water and has enough space for every adult group.
• Caution candidate: may intimidate the shoal, dominate feeding or prey on bite-sized animals.
• Avoid: large enough to swallow the selected or adult Neon Tetra.
• Reassess: chasing, exclusion from food, persistent hiding or abnormal swimming appears after introduction.

No category guarantees the behaviour of every individual. Keep a practical separation plan when introducing any combination whose success depends on temperament, and base the decision on the aquarium’s real dimensions rather than a broad community-fish label.

Answer the key Neon Tetra questions

How big does a Neon Tetra get?

FishBase records a maximum of 2.5 cm standard length for the Neon Tetra; standard length ends at the base of the tail fin. Seriously Fish gives a separate 30 mm standard-length planning reference.

What size aquarium does a Neon Tetra need?

Start with a mature, filtered aquarium having a base of at least 60 × 30 cm, approximately 54 litres for that reference footprint. Measure usable space after decor and plan filtration and every tank mate at adult size.

How many Neon Tetras should be kept together?

Plan at least eight Neon Tetras, with 8–10 given as the species recommendation by Seriously Fish. Do not reduce the group to compensate for a crowded aquarium; choose a setup that supports the complete shoal.

Is a Neon Tetra suitable for beginners?

A Neon Tetra can suit a careful beginner, but our care assessment is intermediate because the aquarium must be biologically mature, ammonia and nitrite must be zero, water must remain stable and the social group and tank mates need planning.

What does this fish eat?

Feed a suitably small complete flake, granule or micro-pellet once daily in an amount eaten within a few minutes. Small live or frozen foods such as daphnia, bloodworm or mosquito larvae can provide measured variety.

What temperature and pH does it need?

Keep it at 21–25°C and pH 5.0–7.0, with hardness of 1–2 dGH; these values are the overlap of the species-level ranges from FishBase and Seriously Fish. Keep ammonia and nitrite at zero and avoid rapid changes.

Are Neon Tetras aggressive or likely to nip fins?

Seriously Fish describes Neon Tetras as generally peaceful. Screen out combinations involving persistent chasing, fin-nipping, territorial exclusion or food competition, and keep the tetras in a group of at least eight with enough usable space.

Which kinds of animals can it live with?

Screen similarly sized characids, gasteropelecids, lebiasinids, smaller callichthyid or loricariid catfishes and non-predatory small-to-medium cichlids for shared water, space and temperament. Avoid fish large enough to swallow it, and treat shrimp, shrimplets, fry and other bite-sized animals as potential prey.

How does a Neon Tetra arrive alive?

Someone must be present to receive the parcel. Start filming every delivery before opening it, showing the sealed parcel continuously as it is opened and the fish still in the sealed bag; inspect it that day, float the bag for 20–30 minutes and never pour the bag water into the aquarium.

Use the bibliography for deeper checking

• FishBase: Paracheirodon innesi — identity, family, distribution, environmental values, natural diet, group record and maximum recorded standard length.
• Seriously Fish: Paracheirodon innesi — aquarium footprint, routine water guidance, filtration reference, diet, layout and behaviour.
• OATA: How to look after tetras and pencilfish — UK group guidance for water quality, feeding, maintenance, introduction and compatibility.
• RSPCA: Fish environment — biological filtration and aquarium waste processing.
• Eschmeyer’s Catalog of Fishes — accepted taxonomic placement and distribution context.
• FishBase: Paracheirodon axelrodi — Cardinal Tetra identity, environmental temperature and maximum-length comparison.
• RSPCA: Pet fish health — general warning signs and escalation guidance.
• MSD Veterinary Manual: Management of aquarium fish — water-quality-led investigation and biosecurity.
• OATA: Find a fish vet — directory for UK veterinary support.
• Tropical Fish Co delivery policy — reception, unboxing-video, acclimatisation and Live Arrival Guarantee procedures.