Cichlasoma flowerhorn

Understand the flowerhorn hybrid

Flowerhorn cichlid (Cichlasoma flowerhorn) is an ornamental hybrid cichlid recognised for vivid colour and the prominent forehead growth called a nuchal hump. It first emerged in Malaysia’s aquarium market rather than evolving as a wild species. This fish suits a keeper prepared to plan its aquarium around adult size, individual temperament, mature filtration and measured water conditions.

The flowerhorn history and hybrid summary records that these fish first emerged during the late 1990s before becoming popular across parts of Asia, Europe and the United States. Appearance can vary substantially between individuals.

Choose it for the right type of aquarium

A flowerhorn suits a keeper prepared to make decisions around the individual fish rather than relying on colour, hump size or dispatch length. American cichlids vary widely in adult size and temperament. Establish the expected adult category, choose the aquarium accordingly and assess any proposed companion against the fish’s observed behaviour.

The identifying features are visual rather than a promise that every animal will look alike. Expect individual differences in colour, markings and head shape. The characteristic form includes a deep body, vivid colouring, pearling, dark flank markings and a forehead hump.

Keep this aquarium fish out of natural waterways

Flowerhorns found outside aquariums result from release. Released populations have become invasive pests in places including Singapore and Malaysia. Never release this fish, aquarium water, plants or other livestock into a pond, river, drain or natural waterway. If your keeping plans change, arrange a responsible aquarium rehoming route instead.

• Identity: ornamental hybrid cichlid
• Defining feature: a nuchal hump on the head
• Planning priority: adult size and individual temperament
• Environmental responsibility: permanent aquarium care or responsible rehoming

Choose the dispatch size with an adult plan

One purchase supplies one animal in the size selected through the live size selector. The listed dispatch sizes are 4–5 cm, 6–7 cm, 7–9 cm and 12–15 cm. The size you select is the size supplied, not the adult size.

Use the dispatch measurement to plan the immediate introduction and feeding portion, then base the permanent aquarium on the fish’s expected adult category and temperament. A larger starting size does not establish sex, maturity or final size.

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

This is a hybrid rather than a wild species, so the care advice here follows its parent group. The gallery images are representative, based on reference photographs of this kind of animal, so colours can look slightly different from the live animal.

Start with the decisive care figures

OATA’s American-cichlid guidance gives 22–27°C, pH 6.5–8.0 and general hardness of 4–12°dH for the group. These are broad parent-group values for planning this hybrid’s aquarium rather than an individual optimum.

Confirm which aquarium bracket applies before committing to the permanent setup. The volume thresholds are starting points: OATA recommends choosing as large an aquarium as reasonably possible because greater water volume makes temperature and water quality more stable.

Prepare before selecting a size

1. Measure the aquarium and confirm its actual water volume.
2. Mature the biological filter before the fish arrives.
3. Test that ammonia and nitrite are both zero.
4. Compare the aquarium’s temperature, pH and hardness with the planning range.
5. Decide whether the aquarium will hold this fish singly or under an assessed pairing or community plan.

Review the current delivery and Live Arrival Guarantee policy before ordering, and use the live selector for the dispatch sizes shown on the product page.

Size the aquarium for the adult category

Choose the permanent aquarium from the adult planning category, not by fitting the fish into the smallest volume that accommodates its arrival size. American cichlids range from smaller fish to animals reaching much larger dimensions, and their space requirements also change with temperament.

Apply the OATA volume thresholds correctly

For a pair of smaller American cichlids that remain under 15 cm, use an aquarium of at least 120 litres. For larger fish over 15 cm, or for a more aggressive individual, use at least 300 litres. Establish the applicable category for this flowerhorn line and individual before stocking.

Aquarium volume affects more than swimming room. A larger body of water changes more slowly when waste, replacement water or room conditions affect it, giving the filter and keeper more opportunity to maintain stable conditions.

Plan for the whole stocking load

Calculate the aquarium around every animal that will live in it. Do not treat the minimum for one category as extra capacity for unassessed companions. Each additional fish increases feeding and waste, and the filter’s bacterial population must expand to process that increased load.

Increase livestock slowly rather than filling all intended positions at once. Rapid stocking can overwhelm the biological filter and cause new tank syndrome, in which ammonia and nitrite rise because too few nitrifying bacteria are processing the waste.

• Before stocking: confirm aquarium volume, adult category and intended social arrangement.
• Before adding another fish: reassess temperament, water quality and the filter’s capacity.
• After any addition: watch behaviour and continue the regular testing routine.

Mature the filter before introduction

A working biological filter is essential. The RSPCA’s aquarium filtration guidance explains that fish release toxic ammonia, beneficial filter bacteria convert it to toxic nitrite, and further bacterial processing produces the safer end product nitrate.

Complete the setup in the right order

1. Install the aquarium and an appropriately functioning filter.
2. Allow the biological filter to mature before introducing the fish.
3. Test the water rather than judging maturity from how clear it looks.
4. Introduce livestock only when ammonia and nitrite both measure zero.
5. Increase the aquarium population slowly so bacterial capacity can grow with the waste load.

Our first tropical aquarium guide explains how to prepare and mature the system before livestock arrives. Clear water alone is not a substitute for testing because dissolved ammonia and nitrite are not assessed by appearance.

Match feeding to filter capacity

Food entering the aquarium ultimately affects water quality. Eaten food becomes fish waste, while uneaten food breaks down directly in the water. Both routes add work for the biological filter. Feed a controlled portion once daily and remove the reason for excess waste by reducing a portion that repeatedly remains uneaten after a few minutes.

Every additional fish and every increase in feeding raises the biological load. Avoid combining a new fish, a major stocking increase and heavier feeding in one unmonitored step. Make stocking changes slowly and keep the established weekly testing routine in place.

Keep water inside the parent-group range

Set and monitor the aquarium within 22–27°C, pH 6.5–8.0 and general hardness of 4–12°dH. Carbonate hardness guidance is 3–10°dKH. Use measured results from the aquarium and tap water when deciding whether the setup is suitable.

Use the readings to make a stocking decision

Test the aquarium before introduction and at least once every week afterwards. Ammonia or nitrite above zero means the biological system is not processing the present waste load safely. Check feeding, stocking pace, filter condition and maintenance before adding further livestock.

Read our water chemistry guide for the role of each measurement, then use the water matcher to compare your measured aquarium values with the range above.

Interpret the nitrate limit carefully

The nitrate figure is measured relative to the normal level in the tap water used for replacement water. If the tap-water reading is 10 mg per litre, the aquarium should not exceed 30 mg per litre under the stated limit. If the tap reading is 20 mg per litre, the corresponding ceiling is 40 mg per litre. Test both sources with the same units so the comparison remains meaningful.

Weekly results are most useful as a sequence. Record the date, ammonia, nitrite, nitrate, pH and temperature together. A result moving towards a limit gives you an earlier maintenance signal than waiting for a visible change in the fish.

Choose substrate and cover for cichlid behaviour

Use fine aquarium gravel or sand. American cichlids may dig or sift the substrate while feeding or breeding, so the base should be chosen with that normal group behaviour in mind.

Plan planting around possible disturbance

Live plants may be dug up or eaten by American cichlids. If planted cover is central to the design, accept that it may be disturbed. Plastic aquarium plants can provide cover without depending on rooted growth, while an open section of accessible substrate makes routine siphoning practical.

Check the substrate during each weekly partial water change. Pass the siphon over areas where solid waste has collected rather than allowing debris to remain beneath cover. The aim is to remove waste while changing part of the water, not to dismantle the whole aquarium each week.

Let maintenance shape the layout

Keep the filter intake and accessible cleaning areas clear enough to inspect for blockages. A design that prevents access to accumulated waste makes the weekly routine harder, while a layout with visible, reachable substrate lets you respond before debris breaks down.

Cover should help the fish use the aquarium without obstructing observation. You should still be able to see the eyes, fins, scales, breathing, swimming and feeding response well enough to notice a change from the individual’s normal condition.

Feed one controlled meal each day

American cichlids are generally omnivorous and often prefer meaty foods. Use specialised cichlid pellets or granules as the prepared portion, supplemented with suitable frozen or freeze-dried foods.

Match the food to the fish’s present size

Smaller American cichlids can take foods such as daphnia, brine shrimp and bloodworm. Larger fish can be offered larger items such as cockles, lancefish or prawns. Choose a piece size the selected dispatch size can take readily rather than assuming one format suits every size.

Feed once a day and offer only what the fish consumes within a few minutes. This schedule creates a clear portion limit and gives you a daily opportunity to observe appetite, swimming and body condition.

Control waste at its source

Overfeeding creates excess faeces and leaves uneaten food to decay. That breakdown releases waste into the aquarium and increases the load on the biological filter. Adding more food is therefore not a neutral decision even when the fish appears eager to feed.

Use one repeatable daily portion as your baseline. If food remains after a few minutes, reduce the next meal rather than extending feeding time. If another fish is present, observe whether both animals can feed without one being displaced; feeding competition is part of the compatibility assessment.

Judge the routine by appetite, body condition and water-test results together. Colour or hump size is not a reason to exceed the portion the fish can consume cleanly.

Complete the weekly water and filter routine

Carry out a 25% partial water change at least once every week. Use a siphon to remove solid waste from the substrate and treat replacement tap water with conditioner to remove chlorine or chloramine before it enters the aquarium.

Use one repeatable weekly sequence

1. Test ammonia, nitrite and nitrate before the maintenance session.
2. Record the results so changes can be compared from week to week.
3. Change 25% of the aquarium water at least once every week.
4. Siphon visible solid waste from accessible gravel or sand.
5. Treat the replacement tap water with an appropriate conditioner.
6. Check the filter and intake for blockages.
7. Observe the fish after maintenance for any change in swimming or breathing.

Protect the filter bacteria during cleaning

Do not rinse established biological filter media under the tap. Chlorine or chloramine may kill the beneficial bacterial population responsible for processing ammonia and nitrite. When cleaning is needed, rinse the media lightly in aquarium water removed during the partial water change.

Testing and maintenance work together. A weekly water change does not replace the need to measure ammonia and nitrite, while a good test result does not remove the need to siphon waste and inspect the filter.

Keep the routine consistent when feeding or stocking changes. A larger food portion or another fish increases waste, so continue watching the results rather than assuming the established schedule will absorb every change automatically.

Use behaviour as an early warning

Learn the individual fish’s normal swimming, colour, breathing, temperament and feeding response. Changes in these areas can give an earlier warning than waiting for a severe visible problem.

Check these signs during the daily feed

• Swimming: watch for hanging at the surface, sitting on the bottom or erratic movement.
• Colour: notice a change to a darker or paler appearance than normal.
• Temperament: note increased aggression or more hiding than usual.
• Breathing: compare whether the gill covers are moving faster or slower than normal.
• Appearance: look for white spots, fluffy growths, damaged fins, lost scales, ulcerations or new bumps.
• Condition: watch for an increase or decrease in body weight and overall condition.
• Feeding: notice reduced intake or a lack of interest in food.

Pair observation with a water test

If behaviour, breathing, appearance or appetite changes, test ammonia and nitrite first and include pH, temperature and nitrate in the same check. Water quality is a direct husbandry factor and gives you an immediate set of measurements to compare with the fish’s usual conditions.

When a concerning change persists, record the test results and the signs you can see, then contact us for health guidance. Do not treat a visible symptom in isolation from ammonia, nitrite, temperature and the recent feeding or maintenance history.

Clear, bright eyes, intact scales, undamaged fins and appropriate swimming are useful comparison points. The most important reference is the same fish’s normal pattern, because individual colour and behaviour can vary.

Choose single or pair housing deliberately

Most American cichlids do better either singly or in pairs, but the appropriate arrangement varies between the different fish in this group. Treat a single-animal setup and a pair as separate plans with different space, behaviour and stocking decisions.

Plan single housing around the whole fish

One purchase supplies one animal, which allows you to assess that individual before considering another cichlid. Confirm its adult category, monitor its temperament and make sure the aquarium meets the applicable volume threshold. Single housing still requires a mature filter, cover, controlled feeding and the complete water-testing routine.

Do not turn two purchases into an automatic pair

A pair is a behavioural relationship, not simply two animals of the same trade name. Sex is not guaranteed for these sizes, and sexing American cichlids varies considerably. Some show obvious differences, while others may show no clear differences unless breeding.

Use at least 120 litres only for a suitable pair from a smaller species remaining under 15 cm. If the adult category is over 15 cm or either individual is more aggressive, the American-cichlid planning threshold rises to at least 300 litres. Confirm that the proposed pair and aquarium fit the same plan before combining them.

Do not add another fish merely to fill visible space. Aquarium volume, filtration and water values must suit every resident, while observed aggression, hiding or loss of feeding access can make an apparently spacious arrangement unsuitable.

Screen every proposed tank mate

There is no universal tank-mate list for this hybrid. American cichlids vary from calmer fish that can sometimes enter robust communities to aggressive individuals that must be housed alone or only with equally aggressive cichlids.

Use temperament as the first branch

Avoid placing an aggressive individual with calmer fish. A shared temperature or pH range is only one part of compatibility; it does not resolve aggression, space use, feeding competition or the extra load placed on the filter.

Complete five checks before mixing

1. Adult category: plan for the mature dimensions of every proposed resident.
2. Temperament: decide whether each animal belongs in a calmer or more aggressive arrangement.
3. Water: make sure the same aquarium can remain within the required ranges.
4. Space: apply the larger or more aggressive threshold when either condition applies.
5. Feeding: ensure the plan lets every fish reach an appropriate portion without persistent displacement.

Ask us for a stocking and compatibility assessment using the aquarium volume, measured water values, present livestock and the size of each fish. Those details allow a more useful decision than matching common names alone.

If you decide a community arrangement is preferable, compare other choices in the South American cichlid collection. Treat that collection as a set of fish to assess individually, not as a list of automatic flowerhorn companions.

Introduce livestock without rushing the filter

Complete compatibility decisions before introducing another fish. Check that ammonia and nitrite are zero, confirm the aquarium is large enough for the intended adult category, and make sure the present fish is feeding and behaving normally.

Add to the biological load slowly

The beneficial bacteria in a mature filter must increase when more fish are added and feeding rises. Rapid stocking can create new tank syndrome because the filter population cannot yet process the extra ammonia and nitrite.

1. Record the pre-introduction ammonia, nitrite, nitrate, pH and temperature.
2. Add livestock only after the compatibility and aquarium-size checks are complete.
3. Keep feeding controlled rather than increasing portions automatically.
4. Continue testing at least weekly and watch behaviour during the daily meal.
5. Pause further additions if aggression, hiding, breathing or feeding changes.

Watch both behaviour and water

Increased aggression, unusual hiding, erratic swimming, reduced feeding or changed breathing may signal that the social arrangement needs attention. Ammonia or nitrite above zero indicates that the biological load also needs attention. Treat these as connected parts of the same stocking decision.

If a social plan cannot be maintained responsibly, use an aquarium rehoming route. Never solve a failed pairing or community attempt by releasing a fish into a natural waterway.

Answer the essential flowerhorn questions

How big does Cichlasoma flowerhorn get?

Plan its permanent aquarium around the adult category established for the individual line, not its dispatch length. OATA uses at least 120 litres for a suitable pair of smaller American cichlids under 15 cm and at least 300 litres for fish over 15 cm or more aggressive individuals.

What size aquarium does Cichlasoma flowerhorn need?

Use at least 300 litres if the fish falls into OATA’s larger, over-15 cm category or shows a more aggressive temperament. The 120-litre threshold applies only to a suitable pair of smaller American cichlids remaining under 15 cm.

How many Cichlasoma flowerhorn fish should I keep together?

Most American cichlids do better singly or in pairs, but assess this hybrid individually. One fish can be planned as a single-animal setup; combine two only after checking pairing requirements, adult category, aquarium volume and temperament.

Is Cichlasoma flowerhorn suitable for a beginner?

It suits a keeper who can mature and maintain a biological filter, test water every week, control feeding and plan around adult size and individual temperament. Prepare the aquarium before introduction and keep ammonia and nitrite at zero mg per litre.

What does Cichlasoma flowerhorn eat?

Feed specialised cichlid pellets or granules with suitable frozen or freeze-dried foods. OATA advises one meal daily, limited to what the fish consumes within a few minutes, with food size matched to the fish’s present size.

What temperature and pH does this fish need?

OATA’s American-cichlid group guidance gives 22–27°C, pH 6.5–8.0 and general hardness of 4–12°dH. Keep ammonia and nitrite at zero mg per litre and nitrate no more than 20 mg per litre above the normal tap-water level.

Is it aggressive or likely to nip fins?

American cichlid temperament varies, and some individuals may be very aggressive. Assess this fish before mixing it, avoid placing an aggressive individual with calmer fish, and keep an aggressive fish alone or only consider equally aggressive cichlids after a complete assessment.

Which animals can live with this flowerhorn?

Calmer American cichlids such as angelfish and severums may enter robust communities with larger shoaling fish, but that rule does not make them automatic companions for this hybrid. Screen every proposal for adult size, temperament, water values, aquarium capacity and feeding access.

How does this fish arrive alive in the UK?

Someone must be present to receive the parcel. Start filming every delivery before opening the sealed parcel, continue without a break while it is opened and show the fish still inside the sealed bag; then float the bag for 20–30 minutes before releasing the fish, and never pour the bag water into the aquarium.

Review the care and identity references

• Flowerhorn cichlid summary — hybrid identity, ornamental history, nuchal hump and consequences of release.
• OATA: How to look after American cichlids — parent-group water, aquarium, feeding, maintenance and compatibility guidance.
• RSPCA aquarium environment guidance — biological filtration and aquarium waste processing.