Three-line Cory

Corydoras trilineatus is one of the most commonly kept cories in the hobby, though it is almost universally sold under the name 'Julii Cory' — a case of widespread misidentification that has persisted for decades. The true C. julii has spots rather than connected stripes forming the lateral pattern; C. trilineatus has three clearly defined, more or less parallel dark stripes, giving it the common name Three-line Cory.

Despite the naming confusion, C. trilineatus is an excellent aquarium fish in its own right — hardy, active, attractive, and widely available at an affordable price. It originates from the Amazon and its Peruvian and Bolivian tributaries and is tolerant of a broad range of water conditions.

Care is beginner-friendly: standard tropical water parameters, fine sand substrate, regular partial water changes, and a group of at least six. The species feeds enthusiastically, schools actively, and is one of the most entertaining of all bottom-dwelling fish to observe as it systematically works across the substrate in formation.

Water: Soft to moderately hard, pH 6.0–7.5, temperature 22–26°C; very adaptable and beginner-friendly. Tank: 60 L minimum with fine sand, some decoration for shelter, and good filtration. Feeding: Sinking pellets, algae wafers, frozen bloodworm, and Daphnia; an enthusiastic feeder. Breeding: One of the most readily bred cories in captivity; cool water change trigger; large clutches possible. Compatibility: Ideal for all peaceful community tanks; excellent with tetras, livebearers, and dwarf cichlids.