Altum Angelfish
Pterophyllum altum
Cichlidae
About
The altum angelfish is the tallest and most demanding of the wild angelfish, native to the blackwater tributaries of the Orinoco and upper Rio Negro. Its body reaches only about 18 cm in length but towers up to 25-30 cm from dorsal to anal fin tip, so it needs vertical swimming space above all else. A relatively peaceful shoaling cichlid, it is highly sensitive to water quality and thrives only in warm, extremely soft, acidic blackwater kept pristine and low in nitrate.
Care
Keep a group of 5-6+ in a very tall, deeply planted tank (60 cm+ height, 300 L+) with warm, extremely soft, acidic blackwater and near-zero nitrate. Best suited to experienced keepers; avoid tiny tankmates it could swallow.
Diet
Omnivore leaning carnivorous. Offer live and frozen bloodworms, brine shrimp and mosquito larvae, weaning onto quality flakes and pellets. Small fish and shrimp are treated as food.
Tankmate compatibility
Gets along with (2)
Possible with care (86)
Avoid (183)
Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.
Telling males from females
What works for this species, most reliable first.
- Extended finsStrong · from about 8 months, and later in a suppressed male
On many cichlids and killifish the male's dorsal and anal fins draw out into trailing points as he matures, while the female's stay rounded.
- VentingA hint only · only on a mature fish, easiest when she is in breeding condition
The method breeders use when the answer has to be right. Hold the fish upside down in a wet hand or soft net and look at the two openings ahead of the anal fin. The forward one is the anus; the one behind it is what you are reading.
- Adult sizeA hint only · only across animals of the same age
In many cichlids, catfish and loaches one sex simply grows larger — usually the male, though there are well-known reversals.
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Frequently asked questions
- What tank size does a Altum Angelfish need?
- A Altum Angelfish needs an aquarium of at least 300 litres (79.3 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.
- What water parameters does a Altum Angelfish need?
- Altum Angelfish does best at 27–32 °C (80.6–89.6 °F), pH 4.5–6.5 and a general hardness of 0–6 °dGH.
- What group size does a Altum Angelfish need?
- Altum Angelfish is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.
- Is the Altum Angelfish suitable for beginners?
- Altum Angelfish is a demanding species best attempted with some experience — it needs stable, closely watched conditions to thrive.