Angelfish

1 Species Overview

Angelfish—also known as the freshwater angelfish or ‘swallow fish’ (燕鱼)—earns its name from the swallow-like grace of its swimming motion when viewed from the side. With an elegant, laterally compressed body, it has long been a favorite among aquarists, to the point that the angelfish has become almost synonymous with tropical fish.

Scientific name: Pterophyllum (Family: Cichlidae). In the trade it is commonly sold as the Common Angelfish.

Distribution: open ocean / marine waters (the ancestral lineage); today almost entirely captive-bred for the aquarium trade.

Other names: swallow fish, angel fish, dwarf angelfish, little sail-fin fish.

2 Appearance

As the name suggests, the angelfish is remarkable for its beauty and poise, and its temperament is gentle. To preserve its elegant shape, it is best kept away from more boisterous tankmates.

Adults reach 12–15 cm in length and up to 15–20 cm in height. The head is small and pointed, the body laterally compressed into a rhomboid (diamond) shape, and the long, tall dorsal and anal fins stand like triangular sails—giving rise to the nickname ‘little sail-fin fish’. Viewed from the side, an angelfish gliding through the water resembles a swallow in flight, which is why it is also called the ‘swallow fish’ in northern China.

Despite lacking vivid coloration, the angelfish is unrivalled in popularity among tropical fish keepers. It is hard to find a veteran tropical-fish hobbyist who has never kept one; mention ‘tropical fish’ and most people picture this clear, otherworldly fish drifting gracefully among the plants.

3 Tank & Water Conditions

Angelfish are not demanding about water quality, and their undemanding, elegant nature makes them easy to keep—another reason for their popularity. Recommended parameters: temperature 24–27°C, general hardness (gH) 3–6 dGH, pH 6.5–7.0.

Some domestic breeding farms use soft water produced by reverse osmosis / deionization during spawning, which helps hatching. However, fry raised in such mineral-poor water then shipped long distances and moved into dealers’ densely stocked tanks with very different water chemistry become stressed and more prone to disease and death. So don’t rush to buy newly arrived fish—let the dealer’s acclimation and quarantine run its course, and buy 7–10 days later; those fish will settle into your aquarium far more reliably, saving you trouble.

4 Feeding

At 24–28°C the angelfish feeds eagerly and grows quickly, so keep the environment as stable as possible for healthy growth.

Foods include brine shrimp, tubifex worms, micro-worms, mealworms, small live fish, and pellets. For fish 3–12 cm long, feed mainly brine shrimp with bloodworms, micro-worms and mealworms as supplements; for fish over 12 cm, use larger items such as bloodworms, tubifex, mealworms and small live fish.

Portion size depends on fish size and count. At home, feed once or twice daily, amount eaten within 5–10 minutes. In large-scale setups feed 2–3 times daily; breeding stock 3–4 times daily. Because angelfish are small with limited appetites, feed to 70–80% fullness and increase frequency to promote growth. For most varieties brine shrimp is the staple; when feeding bloodworms allow 5–10 minutes, tubifex 5–10 minutes (rinse well), and with small fish/shrimp prefer several small meals. Stop feeding 1–2 days before transport.