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

Freshwater angelfish (Pterophyllum scalare) are sold small but grow into tall, territorial cichlids that outgrow the tanks most beginners buy for them. This guide gives you one decisive tank-size recommendation, a single water parameter table, and clear answers on diet and tankmate compatibility so you can set the tank up right the first time.

Meet the Fish: Species Basics

Common freshwater angelfish belong to the species Pterophyllum scalare, a cichlid native to slow-moving, vegetated waters of the Amazon basin in South America. Their body shape is laterally flattened and disc-like — tall from dorsal to anal fin, but thin front to back. That distinction matters for tank shopping: angelfish are not a "long" fish that needs horizontal swimming room so much as a tall fish that needs vertical clearance for its fin display.

Adults reach roughly 6 inches (15 cm) in body length, but total height — including the trailing dorsal and anal fins — typically spans 8 to 12 inches (20–30 cm). That vertical footprint, more than raw gallon count, should drive your tank choice. With good care, angelfish commonly live 8 to 10 years or more.

Tank Size and Height

Sources disagree on the bare minimum, but the practical answer is straightforward:

• 20–29 gallons (76–110 L) is the minimum for one adult or a single bonded pair.
• 55 gallons (208 L) is the realistic starting point if you want more than one fish, plan to raise a group of juveniles to let a pair form, or intend to breed.

Tank height matters as much as volume. Look for a tank at least 18–20 inches (46–51 cm) tall. A long, low "shallow" tank crams an angelfish's fin display, and cramped vertical space is a common early cause of fin damage and stress — not just a cosmetic issue, but a real health warning sign worth watching for in an existing tank.

Simple Stocking Guide

Setup Goal	Tank Size	Minimum Height	Notes
One fish or a single pair	20–29 gal (76–110 L)	18 in (46 cm)	Bare minimum, not ideal for future growth
Small group to grow out (5–6 juveniles)	55 gal (208 L)	20 in (51 cm)	Lets a natural pair form; rehome extras if aggression rises
Breeding pair with fry-rearing space	55+ gal (208+ L)	20–24 in (51–61 cm)	Pair will claim and defend territory
Community tank with tankmates	55+ gal (208+ L)	20 in (51 cm)	Add 10+ gal per additional angelfish or mid-size tankmate

Water Parameters at a Glance

Stability matters more than hitting an exact number. Sudden swings — especially from large, rapid water changes — can cause pH or temperature shock, which is riskier for angelfish than for hardier community fish.

Parameter	Target Range	Notes
Temperature	76–84°F (24–29°C)	Mid-70s to low 80s is the safe zone; 78–84°F supports breeding and fry health
pH	6.0–7.5	Best around 6.5–7.0; tolerate up to ~7.8 if acclimated gradually
General hardness (GH)	3–8 dGH (about 54–145 ppm)	Soft to moderately soft; avoid very hard, alkaline water long-term
Ammonia	0 ppm	Always — no exceptions
Nitrite	0 ppm	Always — no exceptions
Nitrate	Under 20–40 ppm	Maintain with weekly 20–25% water changes
Lifespan	8–10+ years	With consistent water quality and diet

A Note on US Tap Water

Most municipal tap water in the US runs harder and more alkaline than angelfish prefer. Rather than chasing a precise number, acclimate gradually: adjust hardness and pH slowly over days, not in one change, and consider driftwood (which releases tannins that soften and slightly acidify water) or blending in some reverse-osmosis water if your source water is notably hard. Consistency in the tank matters more than matching a lab-perfect target.

Filtration, Flow, and Heating

Angelfish evolved in calm, vegetated water and dislike strong, powerhead-style current — aim for gentle to moderate flow. A sponge filter or gentle hang-on-back filter works well; you can browse filtration options sized to your tank.

A submersible heater is required to hold a stable warm temperature, since 76–84°F is well above unheated room temperature in most homes. Size the heater to roughly 3–5 watts per gallon of tank volume, and choose a reliable model with automatic shut-off protection. Position it where flow carries heat evenly across the tank rather than creating one hot spot near the heater itself.

Diet and Feeding

Angelfish are omnivorous with a protein lean. A practical feeding routine:

• Staple: a high-quality flake or pellet formulated for cichlids or angelfish specifically.
• Supplement 2–3 times weekly: frozen or live brine shrimp, bloodworms, daphnia, or mysis shrimp for extra protein and color.
• Frequency: twice daily in small portions is the practical sweet spot for most home aquarists. Some sources recommend up to 2–3 smaller feedings a day — that's fine as long as each portion shrinks accordingly.
• Portion size: only what the fish clear in 2–3 minutes.

Overfeeding is one of the leading causes of poor water quality, bloating, and "fat," lethargic angelfish. When in doubt, feed less rather than more.

Temperament and Tankmates

Angelfish are peaceful by cichlid standards, but they are not community-safe in the same relaxed way tetras or corydoras are. They establish a pecking order, become territorial (especially when pairing off or spawning), and will eat any fish small enough to fit in their mouth.

Good tankmates:

• Corydoras and other peaceful bottom dwellers
• Bristlenose plecos
• Larger, deep-bodied tetras — bleeding heart, lemon, diamond, rummynose
• Dwarf and pearl gouramis
• German blue rams
• Mollies and swordtails
• Other angelfish, in appropriately sized groups

Fish to avoid:

• Fin-nippers such as tiger barbs and serpae tetras
• Very small nano fish (neon tetras, small livebearer fry) that fit in an angelfish's mouth
• Discus, for beginners (see below)

Angelfish and Discus: Not a Beginner Pairing

Angelfish and discus are often listed together as classic community tankmates because they share similar temperature and water-chemistry preferences. Hobbyist consensus disagrees with that pairing for beginners: angelfish feed faster and more aggressively, and can outcompete or stress discus, which have stricter water-quality demands overall. Save this combination for an experienced keeper running a large tank (75+ gallons) — it's not a good first project.

Sexing and Breeding Basics

Male and female angelfish are very difficult to tell apart outside breeding condition — body and fin shape differences in juveniles are unreliable. The one dependable method is observing the breeding tube when a pair spawns: the female's tube is broader and blunter, the male's more pointed.

Basic breeding notes:

• Sexual maturity arrives around 6–12 months.
• Pairs are monogamous and fiercely guard their chosen territory.
• Eggs are laid on a vertical surface — a broad leaf, slate, or piece of pipe.
• Both parents fan and guard the eggs, which hatch in 2–4 days around 82°F (28°C).
• Fry become free-swimming in about a week to 10 days and need infusoria first, then baby brine shrimp.

Healthy eggs are translucent amber or tan. Eggs that turn white or look fuzzy are unfertilized or fungus-infected; parents often eat these themselves, which is normal maintenance behavior, not a sign of failure.

"Kissing" Behavior Explained

Two angelfish locking mouths looks affectionate, but the meaning depends on context. It can be courtship — a female accepting a male's advances, often after he nudges or pushes her — or a dominance contest between two males sorting out hierarchy. Watch what follows: mouth-locking that leads to spawning is courtship; mouth-locking that leads to chasing and aggression is a dominance dispute.

Common Angelfish (Pterophyllum scalare) vs. Altum Angelfish (Pterophyllum altum)

Altum angelfish are a distinct wild species, not a variety or morph of the common domestic angelfish, and they need considerably more demanding conditions:

Feature	Common Angelfish	Altum Angelfish
Body length	~6 in (15 cm)	~6–7 in (15–18 cm)
Total height	8–12 in (20–30 cm)	Up to 13–14 in (33–36 cm)
Minimum tank	20–55 gal	55+ gal, 20–24+ in tall
pH	6.0–7.5	4.5–6.5
Hardness	3–8 dGH	0–5 dGH, often requires RO water
Temperature	76–84°F	78–84°F
Forgiveness of parameter swings	Moderate	Low

Altums are frequently mislabeled and sold as deep-bodied scalare hybrids. Before paying a premium for a fish marketed as an "altum," confirm its origin and expected adult size and water needs — a scalare-type hybrid raised in altum-strict conditions will struggle just as much as a true altum kept in standard scalare conditions will. Check the current stock in Angelfish, Discus, Rams & Cichlids before buying to compare what's actually being offered.

Common Freshwater Fish Diseases

Angelfish are somewhat prone to a few specific issues, but the disease list below applies broadly to freshwater tanks:

• Ich (white spot disease): a protozoan parasite, the most common freshwater disease; appears as small white spots on skin and fins.
• Fin rot: bacterial, usually triggered by poor water quality or stress.
• Hole-in-the-head disease: linked to stress, poor nutrition, or declining water quality.
• Fungal infections: cotton-like growths, typically following stress or injury.
• Velvet disease: a parasitic infection giving skin a fine, dusty gold or rust coating.
• Dropsy: often bacterial, associated with poor water quality; causes bloating and raised scales.
• Columnaris: a bacterial infection that can spread quickly in a stressed tank.
• Popeye and bloat: swelling around the eyes or abdomen, another issue angelfish show some susceptibility to.

Caring for a Sick Fish

• Isolate the fish in a quarantine tank when possible.
• Watch for early symptoms: clamped fins, appetite loss, color change, visible spots, or labored breathing.
• Test and correct water quality first — ammonia, nitrite, and temperature stability — before reaching for medication.
• Keep the water warm and stable, and keep it clean throughout treatment.

Preventing Disease

• Stick to a consistent water-change schedule.
• Avoid overstocking and overfeeding.
• Quarantine new fish for 2–4 weeks before adding them to the main tank.
• Never introduce unfiltered or untreated water from another tank.
• Keep temperature stable rather than letting it drift.

Medications: Do's and Don'ts

Many over-the-counter medications are effective only against Ich and fungal infections — they are not a general fix. Medication is never a substitute for correcting the underlying water-quality or husbandry problem that triggered the illness in the first place. Some treatments, particularly copper-based ones, are toxic to invertebrates and can stress a fish's organs, so follow dosing instructions precisely and treat in a separate quarantine tank when feasible. A broad-spectrum antibacterial treatment is reasonable to keep on hand for fin rot or other bacterial issues. You can compare treatment and medication options when stocking a quarantine kit.

Common Mistakes to Avoid

• Buying a small or shallow tank because juvenile angelfish look tiny in the store, without accounting for adult height.
• Overfeeding, leading to bloating and ammonia spikes.
• Skipping quarantine for new arrivals and introducing Ich or other disease to an established tank.
• Medicating before checking ammonia, nitrite, temperature stability, and stocking levels.
• Housing angelfish with nano fish or fin-nippers, resulting in eaten tankmates or shredded fins.
• Assuming a store-bought "altum" is the true wild species when it's often a deep-bodied scalare hybrid.
• Mistaking male-on-male dominance sparring for courtship because both look like "kissing."
• Doing large, rapid water changes that shock a species already sensitive to pH and temperature swings.

Frequently Asked Questions

How big of a tank do angelfish really need?

A minimum of 20–29 gallons works for one fish or a single pair, but 55 gallons is the recommended starting point for groups, breeding pairs, or any tank with additional tankmates. Tank height of at least 18–20 inches matters just as much as gallon count, since a shallow tank restricts fin display and can cause fin damage.

What's the ideal water temperature and pH for angelfish?

Target 76–84°F and a pH of 6.0–7.5, with 6.5–7.0 being the sweet spot. Hardness should stay soft to moderate at 3–8 dGH, and consistency day to day matters more than hitting an exact number.

Can angelfish live with other fish?

Yes, with the right choices — larger tetras, corydoras, gouramis, German blue rams, and livebearers all work well. Avoid nano fish and fin-nippers, and expect some territorial behavior, particularly once a pair forms.

Why is my angelfish lip-locking with another one?

It's either courtship, where a female accepts a male's advances before spawning, or a dominance contest between two males establishing hierarchy. Watch what happens next: spawning points to courtship, while chasing and aggression point to a dominance dispute.

What's the difference between a regular angelfish and an altum angelfish?

Altums are a separate wild species — larger, taller, and needing much softer, more acidic water plus a bigger, taller tank than common angelfish. Many fish sold as "altums" in stores are actually deep-bodied scalare hybrids, so it's worth confirming what you're actually buying.

How often and what should I feed angelfish?

Feed twice daily in small portions that clear within 2–3 minutes, using a quality cichlid or angelfish pellet or flake as the staple. Supplement 2–3 times a week with frozen or live brine shrimp, bloodworms, or daphnia for extra protein.

What are the most common angelfish diseases and how do I prevent them?

Ich, fin rot, hole-in-the-head disease, fungal infections, and dropsy are the most frequent issues. Prevention centers on stable water quality, regular water changes, and quarantining new fish; medicate only after confirming parameters are in order.

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

It's very difficult until breeding condition. The most reliable sign is the shape of the breeding tube during spawning — broader and blunter in females, more pointed in males.

Ready to start or expand your setup? Browse available angelfish and compatible cichlids in Angelfish, Discus, Rams & Cichlids on FishyHub.