Mixed Medium Angelfish (Pterophyllum scalare)

Choose an angelfish for a tall, planned aquarium

Mixed Medium Angelfish is a domestic mixed selection of Pterophyllum scalare, the freshwater angelfish. It belongs to the cichlid family Cichlidae and develops the deep, laterally compressed body and extended dorsal, anal and ventral fins associated with angelfish. Domestic selections can include different colours and markings, so choose this fish for its characteristic form and behaviour rather than expecting one fixed pattern.

Eschmeyer’s Catalog of Fishes recognises Pterophyllum scalare as the accepted name. FishBase places it in freshwater habitats across parts of the Amazon basin and records wild adults around dense aquatic and river-edge vegetation in flooded ground or swamps. Those habitats make tall plants, roots and wood useful layout inspiration, while this offer remains a domestic mixed aquarium selection rather than a claim about the origin of an individual fish.

Understand exactly what you are choosing

One purchase quantity supplies one animal of the selected option. Use the live selector to choose between the labels 1 cm, 1,5 - 2 cm, 2.5-3 cm, 3 - 3,5 cm, 4 - 5 cm, 5 - 5,5 cm and XXL (>7 cm). The size you select is the size supplied, not the adult size. These labels describe dispatch size only and should not be read as a life-stage or sex description.

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

The gallery images are representative, based on reference photographs of this species, so colours can look slightly different from the live animal.

We rate this as an intermediate choice because adult height, social behaviour and companion selection need more planning than a small, placid community fish. After checking those needs, you can browse the current angelfish collection for other forms.

Plan the aquarium around adult height and space

A small dispatch fish can grow into a tall adult that needs turning room above, below and around its body. FishBase records a maximum of 15 cm total length, while its current field maximum is 10.5 cm total length. Seriously Fish uses 15 cm standard length and recommends a base of 100 × 40 cm with about 50 cm height. Our practical plan is therefore around 15 cm total length and often 20–25 cm overall height when the extended fins are included, allowing for individual and domestic-form variation.

For an adult pair, plan around 200 litres, a footprint of about 100 × 40 cm and roughly 50 cm of usable height. OATA’s American-cichlid sheet is group guidance; it gives at least 120 litres for a pair of smaller American cichlids and separately says adult angelfish need sufficient height. That lower figure is a floor for assessing a compatible pair, not a promise that every aquarium labelled 120 litres has suitable dimensions.

Volume alone cannot describe usable space. A tall but narrow aquarium may limit turning and territory, while a broad but shallow tank can restrict the fins. Measure the internal water dimensions after allowing for substrate, bracing and the normal waterline.

Our complete freshwater angelfish care guide explains the adult-size and social decisions in greater depth. Make the adult plan before choosing a dispatch size, even when the selected fish looks small in its transport bag.

Build height, cover and clear turning room

Use the aquarium’s height to create structure without filling every route with decor. Tall leafy plants, upright wood and other vertical features can divide sight lines, provide retreat choices and echo the densely vegetated environments occupied by wild freshwater angelfish. Keep an open central or front area where an adult can turn without dragging its fins through leaves or against hard objects.

Lay out the aquarium from the fish’s perspective

• Vertical cover: place tall plants or wood so one fish can move out of another’s direct view.
• Open movement: preserve a route wide enough for a deep-bodied adult to turn comfortably.
• Safe edges: avoid sharp rock, splintered wood or rough openings around long fins and trailing filaments.
• Stable foundations: secure heavier decor because American cichlids may move or sift substrate.
• Gentle circulation: distribute filtered water without making the fish fight a forceful current continually.

Seriously Fish recommends tall leafy planting and a gentle flow for this species. Gentle does not mean stagnant: circulation still needs to carry waste towards the filter and maintain gas exchange. Watch how the fins move. A fish forced to lean into the current or remain behind decor may need the outlet redirected, whereas debris settling everywhere can indicate inadequate circulation.

Fine aquarium gravel or sand gives a practical base. Leave enough clearance beneath wood and around rocks to siphon trapped waste. Plants can be live or artificial if they are secure and have smooth surfaces; the important decisions are cover, access and safety rather than one compulsory plant species.

Check the finished layout

View the aquarium from the front and both ends. If every vertical feature forms one continuous wall, open another route. If one dominant fish can see the entire aquarium from a single position, add a broken sight line. If the tallest fins would enter a lid fitting, heater guard or intake area, move or protect that equipment before the fish grows into the space.

Fit a secure lid while leaving safe access for feeding and maintenance. Check gaps around cables and pipework, and cover hazardous intakes so long fins cannot be pulled against them.

Hold the water inside a stable overlap

Use 24–27°C, pH 6.5–7.4 and about 5–12 dGH as the routine aquarium range. This is the overlap of FishBase’s 24–30°C, pH 6.0–8.0 and 5–13 dGH range, Seriously Fish’s 24–30°C, pH 6.0–7.4 and 0–15 dGH range, and OATA’s American-cichlid guidance of 22–27°C, pH 6.5–8.0 and 4–12 dGH. Treat these values as a stable operating window rather than chasing one exact reading.

Measure the aquarium before making changes. A heater dial is a setting, not a water reading, so confirm temperature with a thermometer. Test pH and hardness before altering tap water or mixing it with reverse-osmosis water. The water chemistry guide explains how GH, KH and pH interact, and the water matcher helps compare measured aquarium water with the stated range.

Respond according to the result

• Inside range and stable: keep the routine consistent instead of adjusting for a different preferred number.
• Outside range but fish appear settled: plan any elective change gradually and measure each step.
• Temperature drifting: check the thermometer, heater operation, room conditions and water circulation.
• Detectable ammonia or nitrite: treat this as urgent water-quality failure rather than waiting for gradual adjustment.
• Changing source water: compare its temperature, pH and hardness with the aquarium before a substantial water change.

Avoid fixed recipes such as an automatic tap-water and reverse-osmosis ratio. Local water and remineralisation methods differ, so the same recipe can produce different GH, KH and pH. Stability comes from testing, recording and repeating a suitable preparation method.

Establish filtration before adding the fish

A working biological filter is essential because fish release ammonia, which is toxic. Beneficial bacteria convert ammonia to nitrite and then nitrate, but the first two compounds must remain at zero detectable levels. The RSPCA’s aquarium guidance explains why a well-established, maintained filter is central to fish welfare.

Do not judge filter maturity by the number of weeks it has been running. Use water tests to show that the system can process waste. If this is your first setup, follow the steps for preparing and maturing a tropical aquarium before arranging livestock.

Match filtration to the aquarium

Seriously Fish gives a turnover of four to five times the aquarium volume per hour for an approximately 200-litre setup, corresponding to a nominal 800–1000 litres per hour. Treat the rating as a starting point because media, pipework and maintenance affect actual flow. Spread the return so the aquarium is filtered without creating a narrow, punishing jet.

Treat replacement tap water with a suitable conditioner before it enters the aquarium. Match temperature closely enough to avoid a sudden swing. Siphon waste from accessible substrate areas and beneath decor rather than relying on clear-looking water as a cleanliness test.

Increase stocking slowly. Every additional fish and every increase in feeding adds waste that the bacterial population must process. If ammonia or nitrite appears after an addition, reduce further stocking pressure, test frequently and act immediately to restore safe water.

Choose a compatible pair or a deliberate group

Angelfish are social, but social does not mean every combination will remain peaceful. OATA advises keeping angelfish as a pair or group at minimum and warns that a single fish may become stressed. FishBase describes aquarium groups of five or more and pairs for breeding, while Seriously Fish notes that they may squabble with their own kind. Combine those points into a practical plan: use a compatible adult pair or a purposefully managed group with enough space and a separation route.

Distinguish a pair from two fish

Two randomly selected animals are not automatically compatible or bonded. They may coexist while young and become territorial as they mature or enter breeding condition. Do not use dispatch size, colour, forehead shape or fin angle to assign sex. Sexing is difficult, and the genital papilla is generally useful only when spawning activity makes it visible.

Watch the group at feeding time and again when food is absent. Brief displays or short chases can occur, but persistent exclusion is different. A fish that remains pinned behind equipment, misses repeated meals, develops damaged fins or cannot cross the aquarium needs intervention.

Prepare the exit plan first

Keep a second mature, suitably sized aquarium ready or identify a realistic rehoming route before conflict begins. A divider can be useful only when each side retains adequate swimming room, filtration, heat and access to food. Moving the aggressor or the excluded fish can change the hierarchy, so continue observing after any rearrangement.

Breeding can intensify territorial behaviour. A pair may defend a broad leaf, slate, glass panel or another vertical surface used for eggs. In a community aquarium, that defended area reduces the usable space for every other fish, which is why a group or breeding plan needs more than the nominal adult-pair volume.

Feed a complete staple and measured variety

Freshwater angelfish are omnivorous. Seriously Fish notes that wild fish feed mainly on zoobenthos such as small crustaceans and other aquatic invertebrates, while aquarium fish accept pellets or flakes and take live or frozen foods. Use that biology to provide variety without allowing one rich item to replace a nutritionally complete staple.

Build the routine in layers

• Staple: offer a complete cichlid pellet, granule or suitable flake in a size each fish can swallow.
• Variety: add suitable frozen or freeze-dried foods such as daphnia, brine shrimp or bloodworm.
• Portion: feed only what the fish consume within a few minutes.
• Schedule: OATA’s American-cichlid guidance uses one measured feeding each day.
• Observation: confirm that subordinate fish receive food rather than watching only the boldest animal.

A controlled feeding study in freshwater angelfish found that feed composition affected growth and reproductive performance. It supports taking dietary quality and variety seriously, but the household routine still needs to be adjusted to fish size, body condition and water quality.

Spread food across more than one point when a group contains a dominant feeder. Watch each fish take and swallow an appropriate item. If one animal repeatedly approaches but fails to eat, check food size, competition, breathing and water quality rather than adding an uncontrolled second meal.

Bloodworm, brine shrimp and daphnia are useful variety, not complete diets by themselves. Avoid using fasting, peas, vitamins or medicated food as automatic responses to abnormal swimming or appetite. A sudden feeding change is a health sign that should trigger water tests and closer assessment.

Acclimatise slowly and check the first week

Prepare the aquarium before the delivery window: confirm zero detectable ammonia and nitrite, stable temperature, secure decor, gentle circulation and a clear release area. Someone must be present to receive live fish, so follow the date and window shown during checkout and in the tracking message.

On arrival

1. Receive the parcel and start filming while it is still sealed, with the outer box visible, before opening it.
2. Open the parcel in one continuous take and show the fish still inside the sealed bag.
3. Float the bag for 20–30 minutes so its temperature can move gradually towards the aquarium temperature.
4. Release the fish gently without pouring transport water into the aquarium.

These steps follow our delivery and Live Arrival Guarantee policy, which also carries the current claim requirements and delivery terms.

Use behaviour as a prompt, not a diagnosis

Some initial caution or hiding can occur after transport, but do not assume every change is normal settling. Gasping, loss of balance, clamped fins, wounds or repeated exclusion require immediate water testing and a prompt response. Check temperature, ammonia and nitrite first because poor water can affect several fish at once.

Add further livestock only after the aquarium remains stable and the existing social pattern is clear. Increasing numbers and feeding quickly can outpace the biological filter. A quiet first week gives you a better view of appetite, aggression and water quality before another variable is introduced.

Act on health changes early

A settled angelfish should show steady swimming, regular breathing, clear eyes, open fins, intact scales, a consistent body profile and reliable feeding. Learn the normal posture, colour and activity of each fish so a change is noticed early. One sign rarely identifies a disease by itself.

The RSPCA’s fish health guidance supports checking visible condition and water quality promptly. OATA highlights changes in swimming, colour, temperament, breathing, appearance, body condition and feeding as reasons to investigate.

If you see a warning sign

1. Test ammonia, nitrite, nitrate and temperature immediately; include pH when chemistry may have changed.
2. Compare the readings with the aquarium’s normal measured values.
3. Inspect every fish for breathing rate, wounds, spots, damaged fins and feeding response.
4. Record when the change began and photograph visible signs.
5. Contact a specialist aquatic retailer or fish vet if the cause or safe response is unclear.

Do not use a universal heat, salt or medication recipe. The correct response depends on the problem, the aquarium inhabitants and the lawful product directions. Isolate an affected fish only when the separate setup is mature, heated, filtered and suitable; an uncycled container can create a second emergency.

If the fish leaves the aquarium, return it to suitable water immediately using wet hands or a wet, soft net, minimise air exposure and monitor breathing, balance and visible injury. Then close the escape route around the lid, cables or pipework. Abnormal recovery needs fish-veterinary attention.

Screen every companion before mixing species

Freshwater angelfish can live in a robust community, but compatibility depends on adult behaviour and dimensions rather than a simple list of names. Seriously Fish describes the species as generally peaceful while warning that it may squabble with its own kind and eat small fish such as tetras. OATA recommends calmer American cichlids such as angelfish only with appropriately robust, larger shoaling fish that share suitable conditions.

Apply five checks to every proposed companion

Avoid very small fish that may be swallowed, persistent fin-nippers and highly aggressive competitors. Treat territorial cichlids, much faster feeders and fish occupying the same preferred space with caution. A calm, robust, appropriately sized shoaling species may be considered when its adult requirements overlap, but individual behaviour still needs observation.

Do not assume that using a different level of the aquarium creates automatic compatibility. A bottom-oriented fish still needs floor space and may encounter angelfish during feeding or breeding. Likewise, a shoal in open water can enter a pair’s defended territory even when it normally swims elsewhere.

Assess the whole aquarium

Compare the adult dimensions and social needs of every inhabitant, then allow room for decor and territories. Check whether all fish can feed without crowding and whether retreating animals have more than one route. If the aquarium already operates close to its space or filtration limit, adding a theoretically compatible species can still create poor welfare.

For a stocking and compatibility assessment, provide the aquarium’s internal dimensions, measured water values, filtration, decor and the exact species and numbers already present. Those details allow a useful decision instead of a universal promise.

Respond to chasing before damage develops

Angelfish remain cichlids, and a previously calm aquarium can change when fish mature, pair or prepare to spawn. Short displays can be part of social negotiation, but continuous pursuit, blocked feeding and forced hiding show that the arrangement is failing. Intervene before torn fins, weight loss or chronic stress develops.

Read the pattern

• Brief chase with recovery: continue observing and confirm that every fish resumes normal movement and feeding.
• One fish controls all food: use separated feeding points and check that the excluded animal eats.
• One fish remains behind equipment: break the sight line and prepare separation.
• A pair defends a vertical surface: treat the surrounding area as lost community space and reduce conflict promptly.
• Fin damage or wounds appear: separate safely, test water and assess the injury.

Rearranging wood or tall plants can interrupt an established line of sight, but decor cannot compensate for inadequate dimensions. A temporary divider is useful only when both sections preserve filtration, heat, movement and feeding access. If dividing the aquarium leaves either side too small, move a fish to another mature setup or use the planned rehoming route.

Adding several fish at once raises both social and biological pressure. The inhabitants must establish relationships while the filter adapts to more waste and feeding. Introduce slowly, then pause long enough to understand the new pattern before making another change.

There is honest uncertainty in every community because individual temperament, pair formation and territory can alter the result. Use the screening rules to reduce predictable risks, maintain the exit plan and judge success by sustained feeding, intact fins, normal movement and access to space.

Check the key decisions before choosing your fish

What is Pterophyllum scalare?

It is the freshwater angelfish, a deep-bodied South American cichlid; this offer is a domestic mixed aquarium selection.

How many Mixed Medium Angelfish does one purchase supply?

One purchase quantity supplies one animal of the selected size option.

Which size options can I select for Pterophyllum scalare?

Use the live selector for 1 cm, 1,5 - 2 cm, 2.5-3 cm, 3 - 3,5 cm, 4 - 5 cm, 5 - 5,5 cm or XXL (>7 cm); each is a dispatch size.

What aquarium does Mixed Medium Angelfish need?

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

Should Pterophyllum scalare be kept alone, as a pair or in a group?

Keep a compatible pair or a carefully managed group; a singleton may become stressed, and two randomly selected fish are not automatically compatible.

What water conditions should I use for it?

Maintain the FishBase, Seriously Fish and OATA overlap of 24–27°C, pH 6.5–7.4 and about 5–12 dGH, with zero detectable ammonia and nitrite.

What should I feed this fish?

Feed a complete cichlid pellet, granule or suitable flake once daily, adding suitable frozen or freeze-dried variety in portions eaten within a few minutes.

How should I acclimatise it?

Start filming before opening the sealed parcel, continue through opening until the fish is visible inside the sealed bag, then float the bag for 20–30 minutes before releasing the fish.

Which companions suit this fish?

Consider calm, robust, appropriately sized fish with overlapping water needs; avoid very small prey-sized fish, persistent fin-nippers and highly aggressive competitors.

Consult the care and identity references

• FishBase: accepted identity, family, distribution, wild habitat, recorded water values and length.
• Seriously Fish: aquarium dimensions, water conditions, diet, behaviour and breeding observations.
• OATA: UK American-cichlid husbandry, social planning, feeding, maintenance and compatibility guidance.
• RSPCA aquarium environment guidance: biological filtration and waste processing.
• Eschmeyer’s Catalog of Fishes: accepted scientific name and taxonomic placement.
• Kasiri, Farahi and Sudagar: controlled angelfish feeding research.
• RSPCA fish health and welfare guidance: visible health checks and early response.