Can corals live in freshwater?

Live corals make stunning additions to marine tanks, cannot survive in freshwater and will gradually die off when placed in this environment.

Are there any signs if they die?

When bleaching events occur, extended heat spikes cause corals to turn a ghostly white, often leading to their death. Colorful bleaching has the opposite effect of dying corals gain more pigment, and glow in shades of bright pink, purple and orange.