Danionella cerebrum

Danionella cerebrum is a remarkable micro-fish from shallow streams in Myanmar and is among the smallest known vertebrates on Earth, reaching a maximum of about 12 mm. Its body is completely transparent, making the internal organs, spine, and developing eggs visible to the naked eye. Originally of intense scientific interest for neuroscience research, it has entered specialist aquarium circles as an extraordinary living display organism. In the aquarium it demands a mature nano tank of 10–20 L with extremely gentle filtration, mature water rich in infusoria and micro-organisms, and densely planted conditions. Diet must consist entirely of micro-foods: baby brine shrimp nauplii, micro-worm, and infusoria for fry. It is entirely peaceful but so small that even gentle water movement can exhaust it. A species-only setup is strongly recommended.

Water: Temperature 22–28 °C, pH 6.5–7.5, GH 3–10; ultra-gentle filtration; mature, stable water. Tank: 10–20 L; species-only nano tank; heavily planted; sponge filter only; dark substrate. Feeding: Baby brine shrimp nauplii, micro-worm, infusoria, and quality nano powder foods. Breeding: Egg-scatterer among fine plants; fry very tiny — infusoria essential as first food. Compatibility: Species-only; too small and delicate for any mixed community setup.