Angelfish Care Guide: Tank Size, Diet, Water Parameters and Temperament

Angelfish are sold as coin-sized juveniles, which is why so many end up cramped in tanks meant for a starter community. This guide covers the tank size, water parameters, diet and temperament an angelfish actually needs as an adult, plus tank mates, types and breeding basics. Get these right from day one and a domestic angelfish is one of the easier centerpiece cichlids to keep.

What Is an Angelfish?

The common freshwater angelfish, Pterophyllum scalare, is a South American cichlid and has no relation to marine angelfish despite the shared name. Three species make up the genus: P. scalare (the fish sold nearly everywhere), P. altum, and P. leopoldi. In the wild they come from slow-moving, soft, acidic, heavily vegetated water across the Amazon, Orinoco and Guiana river basins.

Adults reach about 6 inches (15 cm) in body length and roughly 8 inches (20 cm) tall once the dorsal and anal fins are included. Altums grow noticeably taller than that. Growth is fast — a juvenile bought at quarter-size typically reaches adult size within about a year. Lifespan is commonly cited anywhere from 8 to 15 years; a realistic expectation is about 10 years, often longer with stable water and a varied diet.

Tank Size and Setup

Why Height Matters More Than Length

Angelfish are laterally compressed and swim in a tall, narrow body shape, so water depth matters more than footprint. Aim for 18–24 inches of water depth, which means a "tall" or "high" tank outperforms a standard long tank of the same gallon count.

Minimum Tank Sizes

Setup	Recommended tank
One fish	20 gal tall (75 L) minimum
A bonded pair	29 gal tall (110 L) as a practical minimum
Breeding pair only	20 gal tall works as a dedicated breeding tank
Group of 4–6 or a community	55 gal (208 L) or larger

Sources differ on the single/pair minimum, ranging from 20 to 30 gallons. A 29-gallon tall tank is a safer everyday recommendation than the bare 20-gallon minimum, since juveniles outgrow small tanks quickly and upgrading later is more disruptive than sizing up front.

Filtration, Flow and Decor

A biological filter is required — angelfish produce a meaningful bioload as adults and cannot be kept in an uncycled or unfiltered tank. Air bubbles from an airstone are optional; they only matter if surface agitation isn't already keeping oxygen levels up, and a stream aimed straight at the fish will stress weak-swimming fins.

• Flow: Keep it gentle. A sponge filter, a hang-on-back filter with the output baffled, or a canister with a spray bar all work well. Angelfish are weak swimmers against strong current because of their long fins.
• Substrate: Sand or smooth fine gravel.
• Decor: Tall plants, driftwood, and vertical surfaces such as slate or broad leaves double as spawning sites. Leave open water in the middle of the tank for swimming.
• Lighting: Moderate or dimmed light on an 8–10 hour photoperiod.

Water Parameters

Stability matters more than hitting an exact number. Sudden swings stress angelfish far more than a parameter that sits slightly outside the "ideal" range but stays constant.

Parameter	Safe range	Notes
Temperature	76–82°F (24–28°C)	Some sources list 74–86°F; 78–80°F suits a community, 80–82°F encourages spawning
pH	6.0–7.5	Tank-bred fish tolerate up to about 8.0; wild-caught fish and altums need it lower
General hardness	3–13 dGH (about 50–220 ppm)	Wide tolerance in domestic strains
Ammonia / Nitrite	0 ppm	Non-negotiable; fully cycle before adding fish
Nitrate	Under 20–40 ppm	Controlled with regular water changes

US tap water note: most municipal tap water in the US runs harder and more alkaline than the angelfish's native Amazon basin water. That's fine for domestic strains, which have been line-bred for generations and adapt well to typical US tap water once it's dechlorinated. Save the soft, acidic water for wild-caught fish and altums.

Change 20–30% of the water weekly, or 25% every two weeks in a lightly stocked tank. Avoid chasing a "perfect" pH with chemical adjusters — dosing to force pH down usually causes swings that are harder on the fish than a stable, slightly higher pH.

Heaters

Angelfish need a heater in virtually every US home, since room temperature runs well below their required range. Size for roughly 3–5 watts per gallon, and in tanks over 40 gallons, consider two smaller heaters instead of one large unit — if one fails, the other keeps the tank from crashing to room temperature.

Diet and Feeding

Angelfish are omnivores that lean carnivorous. Build the diet around a quality flake or a small sinking or slow-sinking pellet as the staple, then rotate in frozen or live foods — bloodworms, brine shrimp, mysis shrimp and daphnia — along with some plant matter. You can browse a range of prepared and frozen foods suited to cichlids in FishyHub's food and supplements category.

• Adults: 1–2 small feedings a day, only what they clear in about 2 minutes.
• Juveniles: 2–3 feedings a day to support their fast growth rate.
• Fasting: Skip feeding one day a week to support digestion and prevent bloat.

Temperament and Tank Mates

Angelfish sit in a gray zone between peaceful and semi-aggressive, and both descriptions are accurate depending on context. A young, unpaired fish in a spacious community is generally calm with a mild pecking order. The same fish, once paired and spawning, can turn territorial and claim up to a third of the tank.

They are also predators by nature: an adult angelfish will eat any fish small enough to fit in its mouth, including neon tetras, small rasboras, fry, and shrimp.

Good Tank Mates

• Corydoras catfish
• Bristlenose plecos
• Larger tetras (black skirt, adult cardinals, rummy-nose kept in big groups)
• Pearl or blue gouramis
• Mollies and platies
• Dwarf cichlids such as rams (watch temperature overlap carefully)
• Discus, with caution — see the note below

You can browse corydoras and larger tetras on FishyHub as reliable additions to an angelfish community.

Fish to Avoid

• Fin nippers: tiger barbs, serpae tetras, and similar species will shred an angelfish's long fins.
• Bettas: commonly recommended in some places, but risky in both directions — bettas nip angelfish fins, and angelfish can return the favor.
• Fast, aggressive cichlids that will out-compete angels for food or territory.
• Tiny nano fish, which read as food rather than tank mates once the angelfish is grown.
• Discus caution: the temperature overlap is narrow, and store-bought angelfish can carry disease that's riskier for discus than the reverse. Only attempt this pairing with quarantined, healthy stock and careful temperature matching.

How Many to Keep

Keep angelfish as a single fish, a bonded pair, or a group of five or more — never a group of exactly three, which almost always ends with one fish being bullied out. In a 55-gallon community tank, a workable stocking example is 5 angelfish, 8 corydoras, 12 black skirt tetras, and 1 bristlenose pleco.

Sexing

Angelfish are very difficult to sex until they spawn. The only reliable indicator is the breeding tube (papilla) that appears just before egg-laying: blunt and wide in females, narrow and pointed in males. The standard approach is to buy about six juveniles and let natural pairs form, rather than trying to buy a "matched pair" at the store.

Types of Angelfish

Beyond the three wild species — scalare, altum, and leopoldi — decades of selective breeding produced a wide range of domestic varieties: silver (the original wild-type color), zebra, marble, koi, gold, platinum, albino, leopard, black lace, smokey, half-black, and ghost. Fin types run from standard to veil to super-veil.

Veil Angelfish

The long-fin "veil" trait comes from a recessive gene, so pairing veil to veil produces more veil-finned fry. Because their fins are longer and more fragile, veils need gentler water flow and tank mates that won't nip.

Red Devil Angelfish

A tank-bred line with red-orange coloring and black markings. Care requirements match standard scalare exactly; color intensity deepens with age and a varied, high-quality diet.

Turkey Green ("Avatar") Angelfish

A rarer domestic line that develops a blue-green sheen as it matures, while the juvenile striping fades. Standard scalare care applies, though this line typically costs more than common varieties.

Wild Altums and Regional Forms

Wild-caught altum angelfish and regional forms — Rio Atabapo/Orinoco altum, Santa Isabel, and Rio Nanay "Peruvian altum" — are exported mostly through Colombia and are strictly for advanced keepers. They need very soft water under pH 6.5, temperatures of 82–86°F, and tanks at least 24–30 inches tall, plus careful, slow acclimation. Captive breeding is uncommon and largely left to specialists.

Planted and Biotope Tanks

Angelfish do well in a planted, Amazon-style setup and generally leave plants alone rather than uprooting them. Good choices include Amazon swords, Java fern, anubias, vallisneria, and crypts, along with floating plants to soften the lighting. Driftwood and leaf litter add tannins that echo their natural blackwater habitat.

Breeding Angelfish

Pairs typically form between 6 and 12 months of age. To encourage spawning, raise the temperature to about 80–82°F and feed heavily with live or frozen foods. Provide a flat spawning surface — slate, a breeding cone, or a broad leaf. A single spawn can contain 100 to 400+ eggs, and pairs can spawn again every 7–14 days.

Egg and Fry Care

Eggs hatch in roughly 48–60 hours at 80–82°F, and fry become free-swimming about 4–5 days after that. White eggs are infertile or fungused and should be watched closely. Keepers either leave the eggs with the parents to guard, or move the slate to a separate hatching tank with gentle aeration and a mild antifungal treatment. Once free-swimming, fry need newly hatched baby brine shrimp as a first food.

It's common for young, first-time pairs to eat their own eggs — this usually resolves after a few spawning attempts as the pair matures. If fry numbers outpace your space, local fish stores and hobbyist groups are typically open to trade-ins or rehoming extra juveniles.

Health and Common Problems

Quarantine every new angelfish for 2–4 weeks before adding it to an established tank. At purchase, look for straight (not clamped) fins, no hollow or pinched belly, and a fish that's actively eating in the store tank.

Common health issues include:

• Ich — white spots, usually tied to stress or temperature swings
• Fin rot — often secondary to fin-nipping injuries
• Bloat or dropsy — swollen belly, sometimes with scales standing out like a pinecone
• Popeye — swollen, protruding eye
• Ammonia burns — from an uncycled or overstocked tank

Watch for clamped fins, hiding, or refusing food as early warning signs of any of the above.

Fat or Bloated Angelfish

A swollen angelfish isn't always sick. Possible causes include a female carrying eggs, simple overfeeding or constipation, internal parasites, or dropsy. Scales standing out like a pinecone are the tell for dropsy and warrant prompt attention. For ordinary bloat, fast the fish for 1–2 days and then offer shelled peas or daphnia to help things move along.

A Brief History

Angelfish were imported to Europe in the early 1900s and first bred in the US around the 1920s. Nearly a century of line breeding since then produced the extensive color and fin varieties available today.

Common Mistakes to Avoid

• Buying juveniles for a 10–20 gallon tank and running out of room within a year.
• Adding neon tetras or other nano fish that later become food.
• Housing angelfish with barbs or other fin nippers, leading to shredded fins and secondary fin rot.
• Running strong filter output that pins fish against the glass or stresses their fins.
• Keeping exactly three fish, or dropping a new pair into an established community, which invites bullying or territory takeover.
• Chasing a lower pH with chemical additives instead of accepting stable, slightly harder water.
• Mistaking breeding-tube growth and pre-spawn nipping for illness.

Frequently Asked Questions

How many angelfish can I keep in a 55-gallon tank?

About 4–6 adults alongside small, peaceful community fish. If a pair forms and starts guarding territory, plan for fewer overall to avoid overcrowding conflicts.

Can angelfish live with neon tetras?

It's risky. Neons raised alongside angelfish from a young age sometimes coexist, but adult angelfish usually eat them eventually. Larger tetras, such as black skirts or adult cardinals in bigger groups, are a safer choice.

How do I tell if my angelfish is male or female?

There's no reliable way to sex angelfish before they spawn. Wait for breeding behavior and check the breeding tube — blunt and wide means female, narrow and pointed means male.

Why is my angelfish lying on its side or gasping at the surface?

Test ammonia and nitrite first, since both should read 0 ppm. If water quality checks out, verify temperature and surface agitation for oxygen next.

How fast do angelfish grow?

With good feeding and regular water changes, a quarter-size juvenile typically reaches full adult size in about 8–12 months.

Do angelfish need a heater?

Yes. US room temperatures generally sit below the 76–82°F range angelfish need, so a heater sized around 3–5 watts per gallon is required, not optional.

Ready to start or expand your setup? Browse available angelfish and compatible tank mates in FishyHub's Angelfish, Discus, Rams & Cichlids category.