🐠

Angelfish

Fish

The elegant Amazonian cichlid that pairs for life and rules its corner of the tank!

On This Page▾

🤓 Did you know? Angelfish are cichlids that often form long-term monogamous breeding pairs, and unlike most fish, both parents cooperatively guard their eggs and fry - fanning them with fresh water and defending the territory together. Their tall, laterally flattened body shape is a natural adaptation for slipping between roots and plant stems in flooded Amazon forest, effectively letting them disguise themselves as a drifting leaf.

🗓️ The first week

The numbers a new owner needs in the first week, each from the article it links to. Rows with no link come from the encyclopedia.

Tank size: 29 gallons, tall, for a single adult. A 55-gallon is the better choice for a group of four to six adults, and at a standard 20 inches tall it clears the height requirement on its own.Setup guide →
Height over length: At least 18 to 20 inches tall. A 20-gallon long is often only about 12 inches tall, too shallow for this body shape.Setup guide →
Temperature: 78 to 82°F, tolerating down to about 75°F, with swings held within about 2 degrees. A heater is essential: 3 to 5 watts per gallon, 200 to 250 watts on a 55.Setup guide →
Water chemistry: pH 6.5 to 7.0 and soft water preferred, especially if you want pairs to form. Zero ammonia and zero nitrite matters more here than for hardier community fish.Setup guide →
Filtration: Gentle to moderate flow; angelfish are weak swimmers. A sponge filter if you are breeding, so fry are not pulled into it.Setup guide →
Substrate and decor: Fine sand or small smooth gravel, nothing sharp against those fins. Build vertically: tall driftwood and broadleaf plants break sightlines and double as spawning surfaces. A cover without gaps, since angelfish jump.Setup guide →
Water changes: 25 to 30% weekly from the substrate, with conditioned water at tank temperature. Test nitrate first: under 20 ppm the routine is right, past 40 ppm the next change is 50%.Aquarium Water Changes →
How many: Cichlids, not shoaling fish, so no group-size rule protects them. Either a bonded pair, or enough fish in a big enough tank that aggression spreads. Two or three adults in a modest tank produces a bullied fish.Enrichment guide →
Pairing: Sexing by eye is very difficult. Most keepers raise six or more juveniles and let pairs form; a bonded pair turns noticeably more territorial.Handling guide →
Tankmates: Add angelfish last. Once past roughly 3 inches an adult eats neon tetras and guppies, even ones it was raised with; cardinal tetras are the usual substitute. No fin nippers.Handling guide →
Feeding schedule: Adults once or twice a day, cleared within 2 to 5 minutes. Juveniles 2 to 3 times a day.Feeding guide →
Diet: A quality flake as the staple, with live or frozen protein at least twice a week: bloodworms, brine shrimp, daphnia, mysis. Tubifex only from a cultured source, never wild-collected.Feeding guide →
Off food: Normal for the first 2 to 4 days in a new tank. Past 4 to 5 days, or paired with a sunken belly, clamped fins or stringy white feces, test the water and quarantine.Feeding guide →
Budget: $3 to $50 for a freshwater angelfish, most under $20. Roughly $300 to $600 for a proper tank, then $15 to $40 a month. Marine angelfish are a different group at $150 to $1,500 and need a reef tank.Cost guide →
Lifespan: 8 to 12 years typical, up to around 15.Cost guide →
Adult size: 6 inches (15 cm) body, 8 to 10 inches (20 to 25 cm) including fins.
Quarantine: At least 30 days in a separate tank with its own nets and siphon, 30 to 60 for a fish you especially do not want to lose. Thirty is the floor, not the target.Quarantine guide →
Power outage: Oxygen is the threat, not darkness. Unplug the filter rather than letting it sit dead in the water, and keep the surface moving.Power outage guide →

🚨 Emergency card

Test the water first, then act on these today. Aquatic vets are rare, so nearly all of this is handled at home.

Small white spots like grains of salt, flashing, clamped fins, rapid gill movement: ich, treated by raising the temperature toward 86°F with an anti-ich or copper medication
Pitting lesions on the head and along the lateral line, white stringy feces, appetite loss, fading color
Ragged, receding fins with discolored edges
Fluffy white growths, usually after an injury or a period of stress

Treatment without fixing the water does not hold. Correct the environment, then treat.

From Common Angelfish Health Issues (And What Actually Prevents Them) →

📰 Where to go next

How Much Does Angelfish Ownership Really Cost?

$3 to $50 for the fish, $300 to $600 for the tank that makes it work, and the marine-versus-freshwater price trap.

Angelfish Tank Setup: Height Matters More Than You'd Think

Why height beats length, heater wattage math, pH 6.5 to 7.0, gentle flow, and the lid nobody expects to need.

Angelfish Feeding: Schedule, Diet, and Why They Stop Eating

Schedule by life stage, the 2 to 5 minute rule, what is safe to feed, and the sunken belly that outranks appetite.

Angelfish Aren't Handled, But They Do Get Territorial

The territoriality that arrives with maturity, why angelfish go in last, and how pairs form.

Common Angelfish Health Issues (And What Actually Prevents Them)

Ich, hexamita, fin rot, cotton wool, and why fixing the water outlasts any medication.

Angelfish Enrichment: The Study Found Group Size Did Not Matter

The study that found group size did not matter for this fish, and what to optimize instead.

🛒 What to buy

55-gallon tank and stand, or a 29-gallon tall for a single adult

Hang-on-back or canister filter sized for the tank, gentle to moderate flow

Sponge filter if you plan to breed

Aquarium heater, roughly 3 to 5 watts per gallon

Fine sand or small, smooth gravel

Tall driftwood and broadleaf plants: Amazon sword, Java fern, anubias

Standard LED light

A secure lid with no meaningful gaps

Liquid water test kit

Water conditioner

High-quality flake food

Frozen or live bloodworms, brine shrimp, daphnia, or mysis shrimp

Prices and the reasoning behind each item are in How Much Does Angelfish Ownership Really Cost?.

❓ Frequently Asked Questions

What size tank does an angelfish need?

29 gallons in a tall configuration is the practical minimum for one adult, and 55 gallons suits a small group of four to six adults. Watch out for the "20-gallon long": bigger volume, but often only about 12 inches of height, which is too shallow here. Buy height, at least 18 to 20 inches, before length.

Do angelfish need a tank lid?

Yes. They can jump, so an uncovered tank, or one with meaningful gaps in the cover, is a real risk. The lid is a non-obvious requirement here.

Why is a sunken belly a warning sign even if my angelfish is still eating?

A specific stomach parasite common in cichlids, the family angelfish belong to, can cause a fish to keep eating voraciously while still losing significant weight and developing a sunken belly. Appetite alone isn't a reliable health check for this species.

Browse all animals

📚 Encyclopedia

🐠

Angelfish

Pterophyllum scalare

Animal facts & overview