DI68
Aquarium Advice Freak
I noticed one of my rocks was changing in colour and I thought it was from the new LEDS and was happy until I felt it - it was slippery but firm. I thought maybe this is the beginning of coralline and then it hardens? Googling coralline I came across another link for red slime algae. Threads on here refer to siphoning it but it appears to be stuck to the rock and has also covered a dead part of a coral recently and quickly. Can someone please ID this for me before I start looking at treatments? Thanks