Angelfish Care: A Cichlid Wearing a Party Dress
Last updated: November 2026
Angelfish (Pterophyllum scalare) are Amazon cichlids — intelligent, pair-bonding, territorial, and armed with an appetite sized to their tankmates. They're also the most misunderstood "community fish" in the hobby: sold at quarter-size for 20-gallon tanks they'll physically outgrow. The good news: once you house them like the tall, warm, stable cichlids they are, they're hardy, personable, and worth every gallon they demand.
Quick specs
| Item | Requirement |
|---|---|
| Minimum tank | 29 gal tall (24 in height minimum) for one/pair; 55+ with tankmates |
| Adult size | 6 in body / 8+ in across fins |
| Temperature | 76–82 °F / 24–28 °C; stable, heater + thermometer |
| Water | pH 6.5–7.5, soft to moderately hard; ammonia 0, nitrite 0, nitrate <40 |
| Setup | Tall plants (vallis, sword), open swimming, driftwood, subdued light |
| Filtration | Moderate flow; canister or HOB sized for a heavy-bioload predator tank |
| Lifespan | 8–12 years in good care |
| Diet | Cichlid pellets, frozen brine/bloodworm, quality flake; a little veg |
Tank: height is the spec that matters
Angelfish carry vertical bodies and long fins; a long shallow starter tank is a fish with its dorsal fin bent. Buy height first: 24 inches tall is the working minimum, 30 is comfortable, and 12–15 inches of water column lets them express natural vertical territory-holding. Tall Vallisneria and swords copy their flooded-forest home and give pairs a defensible spawning column (they lay on flat leaves). Flow: they dislike rivers; a canister spray bar or baffle keeps surface exchange strong without blasting. Stocking honesty: a 29 tall holds a pair plus a corydoras school or a small dither group — check the math with the stocking calculator.
Water parameters and maintenance
Warm water plus a centimeter of uneaten cichlid food equals nitrate: 40–50% weekly changes are normal for angel keepers, and ammonia/nitrite must stay at 0 with nitrate under 40 (breeding pairs do better under 20). pH 6.5–7.5 covers wild and domestic strains; consistency beats perfection — their worst enemy is a swing, whether a weekend of missed changes or an overnight crash in very soft water. Angelfish also out-compete most tankmates for surface food and their uneaten pellets sink into substrate; vacuum that substrate weekly or you're farming nitrate.
Temperament and tankmates
Built-in rules: if it fits in the mouth, it's food (neon tetras are the cautionary tale of the hobby); if it nips fins (barbs, aggressive tetras), the angelfish gets shredded. The workable middle is too-big-to-eat, too-calm-to-bother: corydoras, bristlenose plecos (in 55+), cardinal tetras in schools of 10+, and robust medium tetras. Angelfish themselves get bullied by loud barbs and halfbeaks, and a single angel in a community of boisterous fish will sulk off food — see the not-eating guide if that happens. Keep six-plus juveniles together in 55+ gallons if you want a group; otherwise trust the bonded pair.
Common angelfish illnesses
| Illness | Tells | Guide / action |
|---|---|---|
| Ich | Salt grains + flashing; new fish are the vector | Ich guide — angelfish tolerate 84–86 °F treatments with aeration |
| Velvet | Gold sheen, rapid crash, light-avoidance | Not-ich guide — same-day treatment; angels are velvet-prone |
| Internal flagellates / worms | White stringy feces, wasting with appetite | Medicated food with metronidazole or praziquantel/fenbendazole per label; common in wild-caught fish |
| Eye issues (pop-eye, injury) | Clamped, cloudy or bulging eyes post-fight | Clean water + streaks & sores protocol if infected |
| Dropsy | Pinecone, swelling, usually one fish | Bottom-sitting / dropsy — poor prognosis |
| Marbling (not a disease) | Black patches spreading genetically | Nothing — verify ammonia 0 and velvet-negative first, then accept the tattoo |
Prevention
- Quarantine new angels 4 weeks — velvet rides in on "beautiful" wild and farm-raised fish.
- Weekly 40–50% changes; these are warm-water carnivores with a serious bioload.
- Feed soaked cichlid pellets once or twice daily at 60-second portions; one fast day weekly.
- Match tank height and tankmate size to adult dimensions from day one — chronic crowding produces every row in the illness table.
FAQs
Minimum tank for an angelfish?
29 gallons tall (24 in height) for a single or pair, 55+ for community life. Angelfish reach 6 inches tall across fins — plan for that number, not the store size.
Will my angelfish eat the tetras?
Neon and other tiny tetras: yes, sooner or later, especially at night. Cardinal tetras in schools and larger dithers survive; mouth size is the only reliable fence.
Why is my angelfish turning black?
Domestic marbling is genetic and harmless. Rule out ammonia stress and velvet first (test water, flashlight check), then accept the new paint job.
How many angels per tank?
Bonded pairs are cleanest; six-plus juveniles in 55+ gallons if you want a group. Small groups in medium tanks create bullies and stress cases.
Severe cases: consult an aquatic-experienced vet where available.