FishChecker

The Threadfin Rainbowfish (Iriatherina werneri) is a jewel of the aquarium world, celebrated for its exquisite beauty and peaceful demeanor. Hailing from the pristine waters of Papua New Guinea and Northern Australia, this small species typically reaches only 1.5 to 2 inches, making it perfect for smaller community aquariums. Males are particularly stunning, displaying elongated, thread-like dorsal and anal fins that ripple gracefully, often tipped with iridescent blues, reds, and yellows. Their bodies shimmer with a silvery-blue to greenish hue, especially under appropriate lighting. Females are equally charming but possess shorter, more subdued fins. Threadfin Rainbowfish are schooling fish, thriving in groups of at least 6-8 individuals, which not only brings out their best colors but also allows for fascinating social interactions. They are excellent candidates for a planted tank, preferring soft to moderately hard, slightly acidic to neutral water (pH 6.0-7.5) with temperatures ranging from 72-82°F (22-28°C). A well-planted aquarium with open swimming spaces and gentle filtration will make them feel at home. Their small mouths necessitate a diet of fine flakes, micro-pellets, and small live or frozen foods like brine shrimp or daphnia. Peaceful and non-aggressive, they are ideal tankmates for other small, docile species. A lid is recommended as they can be prone to jumping, especially when startled.