Manacapuru Red Back Angelfish (Red Beck)

Choose a tall Amazonian cichlid with an adult plan

The Manacapuru Red Back Angelfish, Pterophyllum scalare, is a freshwater angelfish in the cichlid family Cichlidae. Its documented native distribution covers the Amazon basin in Brazil, Colombia and Peru, with populations also recorded from French Guiana and Guyana. FishBase describes the species as inhabiting densely vegetated swamps and flooded ground where the water may be clear or silty. Eschmeyer’s Catalog of Fishes retains Pterophyllum scalare as the accepted name.

This fish suits an intermediate keeper prepared to provide a mature, tall aquarium, measure water quality and manage changing cichlid behaviour. Plan around the 15 cm adult length FishBase records and an extended-fin height that can reach roughly 20–25 cm. Measure the aquarium's usable height against those extended fins as well as the body length. Plan the aquarium and companions for that 15 cm adult rather than the size supplied.

Keep routine conditions at 24–27°C, pH 6.5–7.4 and 5–12 dGH. These figures are the overlap of FishBase, Seriously Fish and OATA’s group guidance for American cichlids. Stability matters alongside the numbers: establish the aquarium biologically, measure its conditions and avoid abrupt elective changes.

Adult height, social behaviour and territory are the decisive planning points. Our complete freshwater angelfish care guide recommends roughly 200 litres, a footprint around 100 × 40 cm and about 50 cm of usable height for an adult pair. A community or group requires more room, broken sight lines and a practical separation or rehoming plan if conflict develops.

Match the selected dispatch size to your adult plan

One purchase supplies one Manacapuru Red Back Angelfish in the size selected. Use the live size selector to choose 3-3.5 cm, 4-6 cm or XL (6-7 cm). The size you select is the size supplied, not the adult size. Each fish therefore needs the same long-term plan based on a 15 cm adult length, tall finnage and cichlid social behaviour.

Red Beck is a trade name, not a separate species. This fish is Pterophyllum scalare and needs the same care as any freshwater angelfish. Do not infer maturity from a dispatch measurement. A smaller fish still needs an aquarium and social plan capable of supporting its adult dimensions.

Sex is guaranteed only when the selected option explicitly states male or female. This Manacapuru Red Back Angelfish listing has no sex-guaranteed option.

Choose this fish when the aquarium can accommodate its adult height, turning room and territorial behaviour. The intermediate care assessment reflects the need to combine stable water, suitable dimensions, measured feeding and a response plan for aggression rather than relying on the fish’s calm appearance at one moment.

Plan the aquarium around adult height and territory

Use an aquarium of roughly 200 litres with a base around 100 × 40 cm and a height around 50 cm as the smallest adult planning point. Seriously Fish gives those species-focused dimensions, while Tropical Fish Co uses them as the preferred plan for an adult pair. The footprint provides turning and territorial space; the height accommodates the dorsal and anal fins without treating litres alone as the complete answer.

Check three dimensions before litres

• Height: choose an aquarium at least 50 cm tall for the tall adult form.
• Footprint: use around 100 × 40 cm as the starting base rather than a narrow tower with the same nominal volume.
• Volume: plan around 200 litres for an adult pair, with more room for a group or community.

OATA gives at least 120 litres for a pair of smaller American cichlids and separately says an angelfish aquarium must be sufficiently tall. Treat that figure as an industry floor for a compatible pair, not a reason to reduce the preferred 200-litre plan. Two randomly chosen fish are not automatically a compatible pair, and nominal volume cannot prevent conflict when the footprint, layout or social combination is poor.

A group needs substantially more space than the pair plan. FishBase gives aquarium keeping in groups of at least five, Seriously Fish says the species is best kept in small groups, and OATA says angelfish should be kept in a group or as a pair at minimum because a singleton may become stressed. Plan a group's space around adult territory, sight lines and feeding access, not litres alone. Allow for adult territory, monitor access to food and keep another suitable housing route ready before adding a group.

Do not use a smaller aquarium as a temporary welfare plan merely because the selected fish is small. Build around the final adult dimensions from the start.

Shape the layout around long fins and clear escape routes

Create vertical structure with tall leafy plants, wood or roots, while retaining open mid-water lanes where an adult can turn without dragging its fins. FishBase records adults in densely vegetated swamps and flooded ground, and Seriously Fish recommends a well-planted aquarium with tall leafy plants and gentle flow. Use that habitat information as layout inspiration while keeping every structure stable and practical to maintain.

Build useful structure

• Place vertical cover so one fish can move out of another’s direct line of sight.
• Keep an open route through the middle of the aquarium for turning and feeding.
• Choose smooth surfaces around long dorsal, anal and ventral fins.
• Secure wood, plants and other decor so digging or maintenance cannot destabilise them.
• Protect filter intakes and retain access for cleaning and inspection.

Sight-line breaks become especially important when a pair forms or one fish starts controlling a feeding or resting area. Structure should provide more than decoration: each side of a barrier needs usable space rather than a narrow dead end where a subordinate fish can be trapped. Watch where every fish rests, feeds and retreats instead of assuming a planted aquarium automatically offers enough refuge.

Provide gentle circulation without allowing the water to become stagnant. Seriously Fish notes a preference for gentle flow, but the filter must still process waste and support oxygen exchange. Aim outlets so the whole aquarium circulates while leaving calmer areas where the fish is not continually pushing against a strong current.

Check the layout from an adult fish’s perspective. A route that appears wide around a small dispatch fish may be restrictive once the body and fins develop. If a fish repeatedly clips decor, struggles to turn, remains pinned behind a barrier or cannot leave an aggressor’s territory, move the obstruction or revise the social arrangement rather than waiting for fin damage.

Hold stable water within the shared care range

Maintain 24–27°C, pH 6.5–7.4 and 5–12 dGH. This is the shared overlap of FishBase’s species range, Seriously Fish’s aquarium range and OATA’s American-cichlid guidance. Use a thermometer and liquid or suitably precise tests to establish the aquarium’s real conditions instead of relying only on a heater dial or assumptions about tap water.

Test ammonia and nitrite before introducing the fish. Both must read zero. If either becomes detectable after introduction, treat the result as urgent: stop adding livestock and check filtration and feeding at once. Do not wait for cloudy water or visible illness, because toxic nitrogen waste can be present before the aquarium looks dirty.

When pH, GH or KH needs adjustment, first measure both the aquarium and replacement water. The water chemistry guide explains what each measurement means, and the water matcher can compare measured aquarium values with the stated range. Make elective changes gradually and keep a written record so an apparent improvement in one number does not hide instability elsewhere.

Check temperature at different times and after maintenance. Match replacement water closely enough to prevent a sudden shift, and condition tap water before it enters the aquarium. A stable reading within the range is more useful than repeatedly moving conditions in pursuit of one exact number.

Maintain the biological filter before waste becomes a problem

Use a fully established biological filter and confirm zero ammonia and zero nitrite before adding this fish. The RSPCA explains that filter bacteria convert toxic ammonia into nitrite and then the safer end product nitrate. A filter running for a particular number of days is not enough; water tests show whether it is processing waste.

If this is your first aquarium, follow the steps in the first tropical aquarium guide and complete maturation before livestock arrives. Increase stocking slowly because every additional fish and feed increases the load placed on the bacterial population. A sudden increase can overwhelm a filter that previously maintained acceptable readings.

Use a measured weekly routine

1. Test ammonia and nitrite at least weekly and confirm both remain at zero.
2. Check nitrate against the established tap-water baseline.
3. Carry out a 25% partial water change at least once a week, and add further changes when test results call for them.
4. Treat replacement tap water with conditioner before adding it.
5. Check the filter for reduced flow or blockages.
6. Rinse dirty filter media lightly in water removed from the aquarium; do not run it under the tap.

OATA strongly recommends a 25% partial water change at least once every week. Heavy stocking, heavy feeding or rising nitrate calls for more maintenance, and a visually clear aquarium still needs testing. Siphon settled waste from accessible substrate without dismantling the entire habitat at every change.

Watch filter performance after cleaning. A large drop in flow, unusual noise or rapidly rising ammonia requires immediate investigation. Preserve biological media by rinsing it lightly in removed aquarium water, and keep circulation strong enough for waste processing and oxygen exchange without creating a harsh current across the whole aquarium.

Feed a complete omnivore diet in measured portions

Use a nutritionally complete cichlid pellet, granule or suitable flake as the staple, choosing a size the fish can swallow easily. Seriously Fish describes Pterophyllum scalare as omnivorous and records wild fish feeding predominantly on zoobenthos such as small crustaceans and other aquatic invertebrates. Add suitable frozen or freeze-dried foods for variety rather than making one treat the whole diet.

Feed once a day and offer only what the fish can finish within a few minutes. This schedule and portion rule come from OATA’s American-cichlid guidance. Watch each animal eat, because the total amount disappearing does not show whether a subordinate fish received enough. Spread food across more than one accessible point when one individual controls the first feeding area.

Use food response as a daily check

• Every fish feeds steadily: keep portions consistent and remove leftovers.
• Food remains after a few minutes: reduce the next portion and remove the excess before it breaks down.
• One fish hangs back: check aggression, feeding position and body condition rather than simply adding more food.
• Appetite changes suddenly: test water and assess the full set of health signs before changing the diet.

Suitable variety can include daphnia, brine shrimp and bloodworm, which OATA names for smaller American cichlids. These foods complement a complete staple; they do not replace balanced daily nutrition. A controlled angelfish feeding study also shows that feed composition affects growth and reproductive performance, reinforcing the value of choosing a complete diet rather than relying on one attractive food.

Overfeeding adds uneaten material and faeces, increasing the burden on the filter and degrading water quality. Judge the routine by food access, body profile, waste levels and test results. Do not turn appetite alone into a diagnosis, but treat a clear reduction in feeding as a reason to inspect the fish and water promptly.

Follow the arrival sequence before releasing the fish

Prepare the mature aquarium before the parcel reaches you: temperature must be stable, ammonia and nitrite must be zero, and the final social arrangement must already have suitable space. Keep arrival handling separate from chemistry correction; do not begin an elective pH or hardness change while a transported fish is waiting to enter the aquarium. Be at the delivery address to receive the parcel in person, because live fish cannot be left unattended.

Use the Tropical Fish Co arrival procedure

1. Start filming before the parcel is opened, with the parcel still sealed and the outer box visible.
2. Open it in one continuous take and show the fish still inside the sealed bag before anything is disturbed.
3. Inspect the fish on the same day the parcel arrives.
4. Float the bag for 20–30 minutes before releasing the fish.
5. 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. Keep the unboxing video and order number; the delivery and Live Arrival Guarantee policy explains the same-day claim route and its conditions.

After release, assess breathing, balance and swimming without drawing conclusions from colour alone. Persistent gasping, loss of balance, wounds or an inability to swim normally requires immediate water testing and a fish-veterinary assessment. Check temperature, ammonia and nitrite first because those measurements can reveal an urgent environmental problem.

Introduce additional fish slowly over time rather than adding a large community at the same moment. OATA warns that rapid stocking can exceed the filter bacteria’s ability to process increased waste. Once the angelfish is feeding, observe whether every resident can reach food and retreat from territorial interactions.

Respond to health changes with tests before treatment

Look for steady swimming, regular breathing, clear eyes, open undamaged fins, intact scales, a consistent body profile and reliable feeding. Changes in several of these signs give a stronger warning than one brief movement. RSPCA fish-health guidance puts water-quality checks first when visible health signs change.

When a problem appears, test ammonia, nitrite, nitrate, temperature and relevant pH first. Treat detectable ammonia or nitrite as urgent. Compare the readings with the aquarium’s established pattern and correct the environmental cause without making abrupt elective changes to temperature, pH or hardness.

Isolate a fish only in a mature, appropriately heated and filtered setup where separation will not create a second water-quality problem. Photograph visible signs, note when they began and seek a specialist aquatic retailer or fish vet for diagnosis. Use only lawful products labelled for the fish and system, following the product instructions or veterinary direction.

If the fish leaves the aquarium, return it to suitable water immediately using wet hands or a wet, soft net. Minimise handling, then monitor breathing, balance and visible injury. Check the lid and close the route of escape. Abnormal recovery needs fish-veterinary assessment rather than an improvised medication or temperature recipe.

Plan for pairs, groups and changing territory

Keep a compatible pair or a deliberately planned group rather than defaulting to an isolated fish. OATA says angelfish are social and that a singleton may become stressed. FishBase gives groups of at least five for aquarium keeping, while Seriously Fish recommends small groups because individuals may squabble with their own kind. For an adult pair, use the roughly 200-litre, 100 × 40 × 50 cm plan; a group needs substantially more space.

A pair means two compatible fish, not simply two fish placed together. Sex is difficult to determine reliably outside spawning, and the offer does not guarantee it. Begin with enough territory and visual separation to respond if the combination changes. Pair formation or breeding can intensify defence of a vertical surface and the surrounding area.

Watch the whole group, not only the dominant fish

• Confirm that every fish reaches food during the daily feed.
• Look for repeated chasing, confinement to one corner or exclusion from open water.
• Check long fins for new tears and compare both sides of the body.
• Notice whether one individual controls the only sheltered or calm area.
• Act on persistent exclusion before loss of condition develops.

Rearranging decor may interrupt a defended sight line, but it cannot make an incompatible combination safe in inadequate space. Keep a mature separation aquarium or realistic rehoming route ready when planning a group. A divider or spare container without established filtration is not an adequate long-term response.

Breeding behaviour changes compatibility calculations. Seriously Fish records spawning on vertical surfaces and parental guarding of eggs and fry. If a pair begins defending a leaf, slate, glass panel or other site, reassess the available territory immediately. A dedicated mature setup gives a breeding pair and other residents clearer boundaries than a crowded community aquarium.

Screen every companion before mixing species

Choose only companions whose adult size, water range, temperament, feeding speed and territorial needs fit the aquarium. OATA says calmer American cichlids such as angelfish can be mixed in a robust community aquarium with larger shoaling species, but assess each proposed combination individually. Seriously Fish warns that angelfish may eat small fish such as tetras.

Avoid very small fish that may be swallowed, fin-nippers that can damage extended fins, highly aggressive competitors and much faster-feeding species that can leave this fish underfed. These risks remain even when the aquarium looks calm while every fish is young. Judge prey risk and territory using adult dimensions, not the size at introduction.

Larger shoaling fish may be considered when their water requirements, temperament and feeding behaviour overlap, but that category is not a universal tank-mate guarantee. Individual behaviour, pair formation and the aquarium layout can change the result. Monitor feeding access, hiding, chasing, breathing and fin condition after every introduction.

Put every other proposed companion through the same screening questions before adding it. If persistent chasing, injury, prey behaviour or food exclusion appears, separate the animals into suitable mature systems. Do not wait for repeated wounds to establish that the combination has failed.

Answer the key questions before choosing this fish

How big does a Manacapuru Red Back Angelfish get?

It grows to 15 cm long and may stand roughly 20–25 cm tall with extended fins, so choose the aquarium's height for the adult fish, not the size supplied.

What aquarium size does a Manacapuru Red Back Angelfish need?

Plan around 200 litres with a footprint near 100 × 40 cm and about 50 cm usable height for an adult pair; a group or community needs more room.

How many Manacapuru Red Back Angelfish should I keep?

Keep a compatible pair or deliberately planned group. FishBase gives groups of at least five, while OATA says angelfish should be kept in a group or as a pair at minimum and warns that a singleton may become stressed.

Is a Manacapuru Red Back Angelfish suitable for beginners?

It has an intermediate store care rating and suits a prepared keeper with a mature, tall aquarium, reliable water tests and a plan for territorial behaviour.

What does a Manacapuru Red Back Angelfish eat?

Feed a complete cichlid pellet, granule or suitable flake once daily, adding suitable frozen or freeze-dried foods and limiting each portion to what it finishes within a few minutes.

What temperature and pH does it need?

Keep this fish within the 24–27°C, pH 6.5–7.4 and 5–12 dGH overlap of FishBase, Seriously Fish and OATA guidance, with zero ammonia and nitrite.

Is it aggressive or likely to nip fins?

It is a semi-aggressive cichlid that may squabble and become territorial when pairing or breeding. Treat persistent chasing, exclusion or fin damage as a reason to separate fish.

Which kinds of animals can it live with?

Appropriately robust, larger shoaling fish may work when adult size, water needs, temperament and feeding overlap. Avoid very small fish, fin-nippers, highly aggressive competitors and much faster-feeding species.

How does it arrive alive in the UK?

It is bagged in pure oxygen, packed in an insulated poly box with a heat pack when weather calls for it, and carried by a licensed live-animal courier. Receive it in person, film the sealed parcel before opening, inspect it the same day and float the bag for 20–30 minutes before release.

Public references used for identity and care

• FishBase: Pterophyllum scalare — identity, family, distribution, habitat, length and environmental range.
• Seriously Fish: Pterophyllum scalare — aquarium dimensions, water, diet and behaviour.
• OATA: American cichlids — UK group care, maintenance, feeding and compatibility guidance.
• RSPCA: aquarium environment — biological filtration and waste processing.
• RSPCA: fish health and welfare — visible health signs and water-quality response.
• Eschmeyer’s Catalog of Fishes — accepted scientific identity and distribution.
• Kasiri, Farahi and Sudagar — controlled study of feed types in freshwater angelfish.