Teardrop Angelfish

Geographical Origin and Habitat: *Pterophyllum leopoldi* comes from the tropical whitewater and blackwater basins of the Rio Solimões, and in the Amazon River basin between the Manacapuru River and the Santarém region in Brazil. It almost exclusively frequents the marginal flooded zones (Igapó) of very slow-moving rivers, living camouflaged in the dense tangle of roots of trees fallen into the water.

Taxonomy and Morphology: It was described by Gosse in 1963 in honor of King Leopold III of Belgium. Morphologically, when compared to the common Angelfish, the *leopoldi* appears almost "compressed": it lacks the sharp vertical silhouette, presenting a surprisingly horizontal dorsal profile before the insertion of the dorsal fin. The snout also points slightly downward. It is the smallest of the genus, with a standard length rarely exceeding 10 cm (4 inches) and a wingspan (dorsal-anal) of about 15 cm (6 inches).

Social Behavior: Like all Angelfish, in their youth they form cohesive schools that move in unison among the roots. With sexual maturity, they tend to become less gregarious, but rarely fierce. Once the hierarchy is established, intimidating displays (flaring of the gills) replace actual biting. They become extremely trusting and curious if the aquarist avoids sudden movements in front of the tank.

Coloration and Sexual Dimorphism: Its livery, while less flashy than its cousin Altum, is very characteristic. The body has a base color that shifts from pale green to golden-brown, crossed by irregular vertical black bands. The unmistakable distinguishing feature to identify it is the presence of a prominent and well-defined asymmetrical black spot (the so-called "teardrop") positioned on the flank, below the dorsal spine, between the first two broad vertical bands. There are often reddish speckles on the nape and in the eye. Sexual dimorphism is visually absent.

Aquarium Setup: Unlike *Pterophyllum altum*, the *leopoldi* has a much more compact profile and does not require an immense water column. A tank 45-50 cm (18-20 inches) high and at least 100 cm (3 feet) long (about 180-200 liters / 50 gallons) is perfectly adequate to house a group of adults. The ideal setup replicates a tangle of roots: branched bogwood placed vertically, a sand bottom, and an abundant leaf litter (Catappa or Oak). Peat filtration, which tints the water amber and lowers visibility, will drastically reduce their stress and highlight the brilliance of their scales.

Diet and Feeding: Being micropredators, in the wild they sift the biofilm and sludge on trunks in search of microcrustaceans, worms, and insect larvae. In the aquarium, they adapt quite quickly to a prepared diet. It is crucial to regularly feed small live or frozen food (daphnia, white and red bloodworms, brine shrimp) alternated with sinking micro-pellets. It must never be overfed with fatty foods or beef heart, which would irreparably compromise the fish's liver.

Water Quality: They are robust fish but sensitive to polluted parameters. The water must be maintained at consistently warm temperatures (25-29°C / 77-84°F), with a distinctly acidic pH (preferably between 5.5 and 6.5, although they tolerate 7.0) and soft water (GH 2-8). Nitrogenous compounds (ammonia and nitrites) must be strictly zero, and nitrates strictly under 15 ppm. Current in the tank must be limited, simulating a sheltered, slow-moving area of a river bend.

Compatibility and Cohabitation: It is arguably the most peaceful member of the *Pterophyllum* family. It is much less aggressive than the common Angelfish (*P. scalare*) and far less prone to preying on small torpedo-shaped fish (like Neon Tetras), partly due to its proportionally smaller mouth. The best tankmates are other docile Amazonian fish: large schools of Rummy-Nose Tetras (*Hemigrammus bleheri*), Cardinals, medium-small Corydoras, and Loricariids like *Otocinclus* or small *Peckoltia*.

Aquarium Breeding: Compared to domestic Angelfish that lay on any surface even in hard tap water, the *leopoldi* requires very specific conditions (often pure blackwater) to stimulate spawning. Pairs generally lay their eggs on broad vertical leaves (Echinodorus) or on the aquarium glass, often in much more shaded areas than other *Pterophyllum*. Both parents exhibit very strong parental care instincts, looking after the larvae until they are free-swimming.

Risks and Diseases: Their natural shyness can become a problem if housed with overly boisterous or voracious fish, which will cause them to refuse food and waste away. As with Discus and Altums, they are highly sensitive to intestinal parasites (Spironucleus/Hexamita) in the presence of environmental stress or inadequate diets.