Apistogramma nijsseni

Apistogramma nijsseni is recognized by the striking color difference between the sexes. The male has a bluish–gray body with faint yellow reflections and a rounded tail with a broad, bright red band along its outer edge. The female turns lemon yellow, especially during the egg and fry periods; with the black band through her eye, the black spot on her flank and her black-edged fins, she resembles a panda.

Because it lives in very soft, acidic blackwater in the wild, it is choosy about water values. Farm-bred fish are somewhat more flexible, but soft water is needed for successful breeding.

It lives in slow-flowing forest streams that drain into the Ucayali River in the Loreto region of northern Peru. In these blackwaters the pH can drop as low as 4–5 and hardness is almost zero. The bottom is covered by a thick layer of leaves and branches.

• Volume: at least 60 liters for one male and 1–2 females.
• Water: 25–27°C, pH 5–6.5, GH 1–5. If the tap water is hard, it should be mixed with reverse osmosis (RO) water. Peat or dried leaves soften the water and bring out the colors.
• Decor: caves, fine sand, roots, dried leaves; dim light and floating plants.
• Maintenance: a 20–25% change every week with water prepared to the same values; nitrate should be kept low.

Carnivorous. Make small frozen and live foods (brine shrimp, cyclops, daphnia, bloodworms) the staple. It accepts granules once accustomed to them; a varied diet strengthens the female's breeding colors.

Males are more moderate than most Apistogramma, but the female becomes very aggressive while guarding fry. It gets along well with small, calm midwater fish; it hunts shrimp and shrimplets.

Good companions: cardinal tetras, pencilfish, hatchetfish, small rasboras, otocinclus (used to soft water).

Avoid: species that need hard water, large or aggressive cichlids, shrimp, crowds of bottom dwellers.

It is kept as a small harem of one male and 1–2 females, or as a single pair. Each female should have a separate cave. Because males are harsh toward each other, a single male per aquarium is recommended.

The female lays eggs on the ceiling of the cave and takes on their care alone; during this time the panda pattern is at its most distinct. Very soft, acidic water is needed for the eggs to develop properly; in hard water the eggs usually spoil. The fry are fed newly hatched brine shrimp. In a small aquarium, if the female constantly chases the male, the male should be removed.

In the wrong water values it quickly fades and falls ill. Bacterial infections and internal parasites are the most common problems; new fish should be quarantined.

Males reach about 7 cm and are easily recognized by their red-edged tails. Females are noticeably smaller; the panda pattern of a yellow body with black markings is seen only in females.