Weird spots

[raking33]

Hello, can someone please tell me what these red and black spots are?

 

[Timfish]

Sponges are one possibility. I'm guessing this is a new setup, have you read Aquabiomics article?

Establishing a Healthy Microbiome in a New Aquarium Using Live Rock

Studying the effects of live rock in a newly established aquarium shows that high-quality live rock promotes the rapid establishment of an effective biological filter and a microbial community similar to those found in mature reef tanks.

www.reef2reef.com