Macropodus opercularis red velvet

Decide if this paradise fish suits you

The red velvet paradise fish (Macropodus opercularis), sold here as Macropodus opercularis red velvet, is a freshwater labyrinth fish in the Osphronemidae family. FishBase places the species across China from the Yangtze basin southwards, including Hainan and Taiwan, and in northern Vietnam. Its recorded maximum is 6.7 cm standard length. This fish suits a keeper prepared to plan around territorial male behaviour, select companions carefully and maintain a cool, stable aquarium rather than treating it as an automatic community choice.

Adults inhabit varied lowland waters, including river margins, backwaters, small streams, irrigation channels, paddy fields and ditches. They can colonise stagnant, oxygen-poor water because they are obligate air-breathers. The labyrinth organ allows atmospheric breathing, but it does not reduce the need for a mature biological filter, clean water or regular maintenance.

Start with the decisive numbers

Keep the routine aquarium at 20–22°C, pH 6.0–8.0 and 5–12 dGH. This is the overlap between FishBase’s recorded environment, the aquarium values in the Seriously Fish profile and OATA’s gourami and paradise-fish group guidance. Use an aquarium with a base of at least 80 × 30 cm, equivalent to about 72 litres, as the minimum considered for a single pair. A longer or more spacious aquarium gives more scope to separate territories and arrange cover.

Choose the dispatch size with care

One purchase supplies one fish. Use the live size selector to choose between the labels 3 -4 cm, 4 - 5 cm and 6 -8 cm. The size you select is the size supplied, not the adult size. These measurements help you choose the dispatch grade; they do not change the aquarium footprint, water range or long-term compatibility plan.

A smaller dispatch fish still needs an aquarium planned for the species and its social arrangement. Do not begin with a smaller permanent home on the assumption that it can be replaced later. Establish the full aquarium, biological filter, cover and compatible stocking plan before the fish arrives. A larger dispatch grade is also not evidence of sex or final length.

Understand the offer before choosing

Sex is guaranteed only when the selected option explicitly states male or female. This Macropodus opercularis red velvet listing has no sex-guaranteed option.

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 image shows a deep red fish with elongated fins, but use the written identity and care requirements when making the keeping decision. Colour, apparent size and fin shape in a representative image should not be used to promise the sex or individual appearance of the fish received.

Make the purchase decision in the right order

1. Confirm that the aquarium can remain at 20–22°C, pH 6.0–8.0 and 5–12 dGH.
2. Reserve at least an 80 × 30 cm base and about 72 litres for a single pair, with additional space for a more complex social arrangement.
3. Screen every intended companion for temperament, adult size, feeding behaviour and the same environmental range.
4. Choose the dispatch size only after the permanent aquarium plan is settled.

You can also browse our gouramis and labyrinth fish collection when comparing identities and aquarium requirements. Similar family placement does not make two fish compatible; complete the companion assessment separately.

Plan space around the recorded adult size

Plan for an adult of 6.7 cm standard length. FishBase records this as the maximum for male or unsexed Macropodus opercularis. Standard length excludes the tail, so allow for a fish that is longer overall than 6.7 cm.

Choose the aquarium from the 80 × 30 cm footprint rather than calculating space from body length alone.

Use footprint before volume

Provide a base measuring at least 80 × 30 cm, equivalent to about 72 litres, for a single pair. FishBase also gives an 80 cm minimum aquarium size, supporting the importance of horizontal length. The base dimensions matter because two aquariums with similar volumes can offer very different amounts of usable horizontal space.

For example, a tall aquarium should not be treated as equivalent merely because it contains about 72 litres. Check that the base itself reaches 80 × 30 cm. This gives you a clear minimum for arranging wood, plants, shaded areas and visual separation without reducing the full length to a narrow corridor.

Scale the plan with social complexity

The 80 × 30 cm and approximately 72-litre minimum is stated for a single pair. It is not a general allowance for multiple males or a larger mixed-sex group. Males should not be housed together unless the aquarium is very large, and a male kept with females calls for two or more females per male to disperse his attention. That arrangement contains more fish than a pair, so it requires a larger aquarium and a new stocking assessment.

Plan conservatively for an unsexed purchase. The dispatch grade does not establish sex, maturity or final dimensions, and no grade reduces the permanent footprint. Set up the full aquarium before arrival and leave enough open access for maintenance around every piece of cover.

Hold the routine water overlap

Keep this fish at 20–22°C, pH 6.0–8.0 and 5–12 dGH. FishBase records 16–26°C, pH 6.0–8.0 and 5–19 dGH for the species’ environment. Seriously Fish gives 10–22°C, pH 6.0–8.0 and 5–20 dGH for aquarium care, while OATA gives 20–28°C, pH 6.0–8.0 and 4–12 dGH for gouramis and paradise fish as a group. The 20–22°C, pH 6.0–8.0 and 5–12 dGH routine sits inside all three ranges.

Do not choose one extreme from each wider range. A temperature of 26°C fits FishBase but exceeds the Seriously Fish aquarium range, while 10°C fits Seriously Fish but not FishBase or OATA. The 20–22°C overlap produces one clear routine target that respects every named range. Hardness of 5–12 dGH sits inside all three hardness ranges, and all three give pH 6.0–8.0.

Measure before adding the fish

• Temperature: confirm that the aquarium remains between 20°C and 22°C during its normal daily cycle.
• pH: keep readings between 6.0 and 8.0 rather than pursuing a single exact point.
• General hardness: hold the aquarium between 5 and 12 dGH.
• Ammonia and nitrite: both should read zero mg per litre.
• Nitrate: OATA advises that it should not exceed 20 mg per litre above the normal tap-water level.

Use our water chemistry guide to understand the measurements, then compare your actual readings with the target through the water matcher. Record the figures rather than relying on the aquarium’s appearance.

Respond to a reading, not a guess

If the aquarium measures 23°C, it is above the routine overlap even though it remains inside some broader ranges. Bring the setup into the 20–22°C target before introducing the fish. If pH is 7.2 and hardness is 8 dGH, both readings sit within the plan; stability inside the range is the goal.

Atmospheric breathing is not a substitute for water quality. The labyrinth organ helps the fish use air at the surface, but dissolved waste still affects its health. Keep the filter mature, test regularly and investigate any movement away from the established baseline.

Build cover without losing filter capacity

Set up a fully decorated, biologically mature aquarium with a working filter, wood and plant cover. Driftwood roots and branches can be placed to form a few shady spots. If you aim to breed the fish, include some floating or surface vegetation. Leave practical access around the décor so waste can be removed and the filter intake remains clear.

A natural-looking arrangement can use branches, roots and dried leaf litter. Seriously Fish notes that leaf litter adds cover and supports microbe colonies that may provide early food for fry. That benefit relates especially to breeding and fry care; routine adult feeding still needs a deliberate diet.

Match filtration to the aquarium

For an aquarium of about 72 litres, Seriously Fish gives a turnover of four to five times the volume each hour and a filter rating around 290–360 litres per hour. The calculation is practical: four times 72 litres is 288 litres per hour, while five times is 360 litres per hour. Choose the filter by its stated flow and the aquarium’s actual volume, then keep it free of blockages.

The RSPCA’s aquarium welfare guidance explains why filtration is essential. Fish release toxic ammonia; bacteria in a working biological filter convert it to nitrite and then to the safer nitrate. Air-breathing ability does not perform that process or remove dissolved waste.

Mature the biological filter first

Prepare and mature the aquarium before livestock is introduced. Our first tropical tank guide explains the setup sequence. Confirm zero ammonia and zero nitrite before adding this fish, and increase the total aquarium population slowly so the bacterial colony can respond to increased waste and feeding.

A newly filled aquarium is not mature simply because temperature and pH are correct. The biological filter must already be processing waste. OATA warns that adding too many fish too quickly can cause new tank syndrome, with ammonia or nitrite rising because the bacterial population cannot handle the new load.

Feed small animal foods in controlled portions

Base the diet on small live or frozen animal foods. FishBase records wild adults feeding on small aquatic animals, including small fish, while Seriously Fish considers insect larvae and similar prey likely in nature. Suitable aquarium foods named by Seriously Fish include Daphnia, Artemia, white worm and grindal worm. These choices directly match the species’ recorded feeding biology.

High-quality dried products may also be accepted, particularly by commercial strains. Treat acceptance as something to observe in the individual fish rather than assuming every product will be eaten. Freeze-dried Artemia and freeze-dried Daphnia are named dried choices, but varied live or frozen prey-sized foods remain the clearest match for the recorded diet.

Use OATA’s feeding schedule

OATA’s gourami and paradise-fish sheet gives the group routine: feed once a day and offer only what the fish can finish within a few minutes. This controls the portion without relying on a fixed number of pieces, which would vary with food size and the fish’s dispatch grade.

1. Choose a prey-sized live, frozen, freeze-dried or accepted high-quality dried food.
2. Offer a small amount and observe active feeding.
3. Stop when the few-minute feeding window has passed.
4. Remove uneaten food so it does not break down in the aquarium.
5. Vary the named foods instead of relying on one item at every meal.

Read appetite alongside water quality

Reduced intake or a loss of interest in food can be an early sign of a problem. Check whether the food is appropriate and then test ammonia, nitrite, nitrate, temperature, pH and hardness. Do not answer poor appetite by repeatedly adding more food, because uneaten material can release waste and make water conditions worse.

A dispatch-size difference can change the size of food that is easy to take, but it does not change the once-daily schedule or the few-minute portion rule. Break or select foods to suit the fish’s mouth, observe each feeding and remove anything left behind.

Follow a weekly maintenance routine

Change 25% of the aquarium water at least once every week. Use a siphon to remove solid waste from the substrate while taking out the old water.

For a 72-litre aquarium, a 25% change is 18 litres. Measure the actual working volume if décor or a different aquarium size changes the amount of water present. Treat replacement water with tap-water conditioner before adding it so chlorine or chloramine does not damage the fish or biological filter.

Combine the change with essential checks

• Test ammonia and nitrite at least once per week; both should remain at zero mg per litre.
• Check nitrate against the normal tap-water level and keep it within OATA’s limit.
• Confirm that temperature remains 20–22°C, pH 6.0–8.0 and hardness 5–12 dGH.
• Inspect the filter for blockages and confirm that water is moving normally.
• Siphon visible solid waste rather than leaving it to decay.

Do not rinse filter media under the tap. When the filter needs cleaning, rinse the media lightly in aquarium water removed during a partial change. This reduces the loss of the beneficial bacteria that process ammonia and nitrite. The aim is to clear obstructing debris without stripping the filter back to an immature state.

Use the first month to establish a baseline

During the first week, note normal feeding response, swimming, colour, breathing and use of cover. Pair those observations with measured water values. During the following weeks, keep the same testing and water-change rhythm so changes are compared with a real baseline rather than memory.

If ammonia or nitrite rises above zero, treat the reading as a water-quality warning. Check stocking pace, feeding, uneaten food and filter function. OATA explains that bacterial capacity must increase when more fish and food are added, so avoid adding several further animals before the aquarium has remained stable under its present load.

A larger aquarium can make temperature and water quality more stable, but it still needs the same scheduled care. Volume gives a wider buffer; it does not replace testing, conditioned replacement water, substrate cleaning or filter checks.

Follow the arrival sequence in order

Film every delivery from the sealed parcel before opening it, then float the bag for 20–30 minutes before releasing the fish. The current Tropical Fish Co delivery and Live Arrival Guarantee policy sets out the packing, receipt, video and acclimatisation steps.

1. Start a continuous video before opening. Show the parcel still sealed with the outer box visible.
2. Open the parcel in the same continuous take. Keep filming without interrupting the sequence.
3. Show the fish inside the sealed bag. Record its condition before anything is disturbed.
4. Float the bag. Keep it floating for 20–30 minutes before releasing the fish.
5. Keep bag water out of the aquarium. Release the fish without pouring the transport water into the tank.

The fish is hand-bagged in pure oxygen and packed in an insulated poly box, with a heat pack when the weather calls for it. Those measures support transport, while the aquarium still needs to be fully prepared, mature and within the required water range before the parcel is opened.

Prepare the aquarium before receipt

Be at the delivery address to receive the parcel, because live fish must not be left unattended. Confirm 20–22°C, pH 6.0–8.0, 5–12 dGH, zero ammonia and zero nitrite in advance. Make sure the filter is operating and that wood or plant cover is already arranged. Acclimatisation is not the time to finish decorating, mature a filter or decide where incompatible fish will be moved.

Keep the claim evidence complete

Open and inspect the parcel on the day it arrives. If there is a Live Arrival Guarantee issue, send the order number and continuous unboxing video the same day. The video should show the sealed parcel, the uninterrupted opening and the fish still inside its sealed bag before release.

After release, compare the fish’s breathing, posture, colour and swimming with the health observations below. Use measured water readings whenever behaviour changes; transport appearance alone should not replace an aquarium test.

Act on changes in health or behaviour

Watch for changes in swimming, colour, temperament, breathing, body condition, fins, scales and feeding. OATA recommends learning the normal appearance and behaviour of each fish so that a change is recognised early. Small variations are normal, so compare each fish with its own usual behaviour and appearance.

Pair each observation with an action

This species must visit the surface to breathe atmospheric air, so a normal surface breath is part of its biology. A changed pattern of prolonged surface hanging or altered gill movement still deserves a water test. Air breathing does not protect it from ammonia, nitrite or poor maintenance.

Start with the aquarium

Check that ammonia and nitrite remain at zero mg per litre, nitrate stays within the OATA limit, and the aquarium remains at 20–22°C, pH 6.0–8.0 and 5–12 dGH. Inspect the filter for a blockage and look for uneaten food or accumulated waste.

Test the water as soon as you see any of these changes. Different problems can produce similar changes, while unsuitable water can cause or intensify many signs. Record the readings and observations, then contact us for further guidance when a health change persists or the fish’s condition concerns you.

Daily observation works best alongside the weekly routine. Feeding time gives a useful opportunity to check appetite, swimming, fins, scales and interactions without adding another disturbance to the aquarium.

Screen community fish before mixing

Treat every community match as conditional. Seriously Fish says this species can be maintained alongside peaceful schooling fish with comparable environmental requirements, but similarly shaped fishes should be avoided. OATA says paradise fish can be semi-aggressive and are usually best kept on their own, and recommends robust companions if they are mixed.

A candidate companion must fit 20–22°C, pH 6.0–8.0 and 5–12 dGH. Matching temperature alone is not enough. Compare adult size, temperament, feeding behaviour and body shape, then assess whether the aquarium has enough footprint and cover for every animal.

Avoid the named risks

• Similarly shaped fishes: Seriously Fish says they should be avoided.
• Timid species: OATA says to avoid them with paradise fish.
• Small fish that could be eaten: avoid them; FishBase records small fish among the wild diet.
• Fish that may nip fins: OATA says to avoid them with paradise fish.
• Other males: do not house males together unless the aquarium is very large.

“Peaceful schooling fish” is a screening category, not a universal approval. A schooling fish that needs warmer water, is small enough to be eaten or may nip fins fails the assessment even if its general temperament is peaceful.

Use a four-part companion check

1. Does the candidate remain healthy at 20–22°C, pH 6.0–8.0 and 5–12 dGH?
2. Is it peaceful but not timid, and robust enough to live with a paradise fish that can be semi-aggressive?
3. Is it neither similarly shaped nor small enough to be treated as prey?
4. Will it leave the paradise fish’s fins alone and feed without overwhelming it?

Only proceed when all four answers are satisfactory and the aquarium has adequate space. Introduce population increases slowly so the biological filter can adjust, and observe changes in aggression, hiding, feeding and fin condition.

Manage male territorial behaviour

Plan around territorial males. FishBase states that males fight each other, while Seriously Fish says male territorial aggression becomes more pronounced during reproductive periods. Males should not be housed together unless the aquarium is very large.

Do not use dispatch size, colour or the representative gallery image to construct a sex ratio. The offer is unsexed, and the size selected describes only the fish’s dispatch measurement. A conservative plan is to prepare for one fish unless a deliberately assessed social arrangement and suitable additional space have been established.

Understand the pair minimum

Seriously Fish gives an 80 × 30 cm base and approximately 72 litres as the minimum considered for a single pair. That footprint does not automatically cover a trio, several females or multiple territories. It also does not override the warning against housing males together.

Where a known male is deliberately kept with females, Seriously Fish advises two or more females per male to disperse male attention. That advice creates a group of at least three fish, so use a larger aquarium than the pair minimum and arrange multiple areas of cover. For a trio or larger group, provide at least 100 litres, the minimum OATA’s gourami and paradise-fish group guidance gives for paradise fish, and assess the footprint, territories and total biological load together.

Watch interactions, not just injuries

• Increased hiding can indicate that one fish is being displaced.
• A change in feeding can show that a fish is not reaching food comfortably.
• More pronounced aggression calls for an immediate review of territories and stocking.
• Fin or scale damage requires prompt water testing and a compatibility response.

Wood, branches, plants and shaded areas can break up the aquarium visually, but décor does not make an unsuitable social combination safe. The strongest controls are avoiding other males except in a very large aquarium, excluding timid or vulnerable fish and giving any planned group substantially more room than the pair baseline.

Reassess the arrangement during reproductive behaviour, when male territorial aggression becomes more pronounced. Bubble-nest behaviour is part of reproduction, but it should not be treated as evidence that every nearby fish is being tolerated safely.

Use a case-by-case stocking plan

Choose companions for the exact aquarium you have. Peaceful schooling fish with comparable environmental requirements are the clearest candidate category, but they still need individual screening. Robustness, adult size, body shape, fin behaviour and water requirements all matter.

Work through common scenarios

Invertebrates require an individual assessment because FishBase records this species feeding on small aquatic animals. Size, behaviour and vulnerability must be considered rather than assuming that every shrimp, snail or other invertebrate is safe. Do not keep it with fish small enough to be eaten.

Review the complete load

Compatibility is not only about whether fish fight. More animals increase feeding and waste, requiring the biological filter’s bacterial population to adjust. Add fish slowly, keep ammonia and nitrite at zero, and retain the weekly maintenance schedule while observing the new social pattern.

Before a mixed stocking plan is put into practice, write down each animal’s adult size, temperature, pH, hardness and temperament. Remove any candidate that falls outside 20–22°C, pH 6.0–8.0 or 5–12 dGH, then apply the behavioural exclusions. This prevents an appealing but unsuitable species from remaining in the plan simply because one parameter matches.

If a proposed companion falls outside these categories, leave it out unless it passes every water, size, temperament, body-shape and fin-nipping check above.

Answer common paradise fish questions

How big does Macropodus opercularis red velvet get?

FishBase records a maximum of 6.7 cm standard length for Macropodus opercularis. Standard length excludes the tail; plan its aquarium from the 80 × 30 cm footprint rather than body length alone.

What size aquarium does Macropodus opercularis red velvet need?

Use a base of at least 80 × 30 cm, equivalent to about 72 litres, for a single pair. Seriously Fish gives this as the minimum considered; larger or more complex social arrangements need more space.

How many of this fish should I keep together?

Plan conservatively around one unsexed fish. Seriously Fish gives a single-pair baseline and advises two or more females per male when a known male is kept with females; males should not share unless the aquarium is very large.

Is Macropodus opercularis red velvet suitable for beginners?

Macropodus opercularis red velvet needs deliberate care rather than automatic community placement: maintain 20–22°C, pH 6.0–8.0 and 5–12 dGH, mature the filter and plan around territorial male behaviour.

What does this paradise fish eat?

Feed small live or frozen Daphnia, Artemia, white worm or grindal worm, with accepted high-quality dried products for variety. OATA’s group routine is once daily, limited to what it eats within a few minutes.

What temperature and pH does Macropodus opercularis red velvet need?

Keep Macropodus opercularis red velvet at 20–22°C and pH 6.0–8.0, with hardness of 5–12 dGH. These are the overlapping routine values from FishBase, Seriously Fish and OATA guidance.

Is Macropodus opercularis red velvet aggressive or a fin-nipper?

Male Macropodus opercularis red velvet are territorially aggressive and fight other males. Paradise fish can be semi-aggressive, so avoid similarly shaped fish, timid species and companions that may nip its fins.

Which fish can live with this paradise fish?

Consider peaceful schooling fish with comparable 20–22°C, pH 6.0–8.0 and 5–12 dGH requirements after individual screening. Avoid timid, similarly shaped or very small fish and any companion that may nip fins.

How does this fish arrive alive in the UK?

It is bagged in pure oxygen and placed in an insulated poly box, with a heat pack when weather calls for it. Film the sealed parcel before opening, float the bag for 20–30 minutes before release, and be in to receive it.

Consult the care references

• FishBase: Macropodus opercularis — identity, family, distribution, recorded environment, maximum length, wild diet and male behaviour.
• Seriously Fish: Macropodus opercularis — aquarium footprint, volume, filtration, décor, water, feeding and compatibility.
• OATA: How to look after gouramis and paradise fish — group water, feeding, maintenance, introduction and health guidance.
• RSPCA aquarium environment guidance — biological filtration and waste processing.