Two-spot pike cichlid

Two-spot pike cichlid (Wallaciia notophthalmus) is a true dwarf pike from the lower Rio Negro. Despite its small size, it behaves like a miniature predator with attitude. Females flash bold eye-spots in the dorsal fin, males carry a quirky raised crest, and established pairs will zealously guard a cave nest. This is an advanced, blackwater specialist that rewards careful, thoughtful care.

• Size: up to 7.6 cm SL
• Lifespan: 4-6 years
• Temperament: semi-aggressive
• Water: very soft, acidic freshwater (pH 4.5-6, 1-4 dGH)
• Temperature: 24-28 C
• Diet: carnivore; prefers live/frozen foods
• Minimum tank: 45 US gallons
• Care level: advanced

Origin and habitat

Native to the Amazon basin, specifically the lower Rio Negro, this species comes from classic blackwater: tea-stained, very low in minerals, and acidic. Leaves, branches, and roots create a maze of cover. Light is subdued and the water is clear despite the dark tint. Those conditions shape its preferences in aquaria.

Aquarium setup and water

Give this fish space and structure. A 45-gallon tank is the starting point, even though it is small, because it is territorial and appreciates room to establish a patch. Break lines of sight with wood and botanicals, and provide several tight caves or narrow tubes for retreat and spawning. Dim lighting suits it well.

• Temperature: 24-28 C
• pH: 4.5-6
• Hardness: 1-4 dGH (very soft)

Filtration should be efficient but not blasting; this fish appreciates clean, well-oxygenated water without harsh currents. Regular, moderate water changes help, but avoid raising pH or hardness with your replacement water.

Diet and feeding

A carnivore by nature, it responds best to live and frozen invertebrate prey. Offer insect larvae, Artemia, and small crustaceans. Many individuals ignore dry foods entirely, so plan to stock quality frozen options and be ready to use live foods to get new fish eating.

Behavior and tankmates

Semi-aggressive and quite territorial, especially once a pair forms. It is a small predator that will view tiny fish and shrimp as food. Keep a single fish or a compatible pair in a carefully aquascaped tank, or choose tankmates that are robust, fast, and occupy different levels while tolerating very soft, acidic water.

• Avoid other pike cichlids or similarly shaped bottom dwellers in modest tanks.
• Do not mix with very small fish or shrimp that can be swallowed.
• Provide multiple caves so subdominant fish have options to retreat.

Breeding

Captive breeding is documented. This species is a cave spawner with clear role differences: females display bold dorsal eye-spots during courtship and tend the eggs, while males usually defend the surrounding territory.

To encourage spawning, offer several snug caves (ceramic tubes, narrow rock crevices, or coconut shells) and keep the water very soft and acidic. Once a pair settles on a site, they will guard it intensely. After hatching, the fry require tiny live foods; newly hatched Artemia nauplii are a common first food. Tankmates should be removed or the pair kept alone, as nest defense is vigorous and other fish may eat fry.

Common problems and how to avoid them

• Hard, alkaline water: Leads to chronic stress and poor condition. Use very soft, acidic water within the stated ranges.
• Refusal of dry food: Many individuals never accept pellets or flakes. Keep a steady supply of suitable live/frozen foods.
• Territorial aggression: Provide ample cover, broken sight lines, and multiple caves. Be prepared to separate fish if a pair forms and persecutes others.
• Cramped quarters: Despite their size, they need space. Start at 45 gallons and avoid overcrowding.