Celestial pearl danios are from Southeast Asia, specifically Myanmar, Thailand, and Sumatra. For this reason, these tropical fish can’t tolerate cold water well.
They require a warm environment when kept in captivity. You must maintain the water temperature at around 73°F to 79°F (22.7°C–26.1°C).
Moreover, these freshwater fish generally live in small, densely vegetated shallow ponds. To keep them comfortable in captivity, their tank must be heavily planted with live aquatic plants, preferably those present in their natural habitats, such as elodea waterweeds and Brazilian waterweed. These plants provide shelter so they can hide whenever they feel threatened or stressed.