Alien rock?

[Chris kindley]

I got this piece of rock in an equipment bundle I bought. It glows like this after being under my actinic lights. What in the world makes it so this and is it safe for my tank?

 

[dakoop]

Kryptonite

 

[1fishjones]

Probably Dinoflagellates, otherwise known as bioluminescent plankton, they can show up in shades of blue, green, orange, & red. There's a bay in Puerto Rico where they're so thick the water sparkles a rich neon blue if you run your hands through it. Cool stuff, consider yourself lucky for now. I understand they usually don't last long in an aquarium.