What are these red/orange spots showing up on my rock?

[Subliminal]

 

[mwil79]

Those would be flatworms.

Red Planaria which are a pain, pick up a wrasse to start the natural way of eliminating them.

 

[mnat]

Yeah, you can also use flatworm exit, but be careful they can release toxins when they die and if you have a lot of them (and it looks like you do) just use carbon.