Critter ID in reef

[ETH2ETH]

Just noticed these little guys crawling on my glass. I can count at least 30 of them and they kind of slither around to move.

 

[olonmv]

Flatworm of some type. White lights will help the experts out.

 

[olonmv]

Some eat coral.

 

[MaxTremors]

They look like red planaria. Harmless, though they can get to plague proportions and smother corals. They are primarily photosynthetic but will also eat film algae and copepods. Some wrasses and dragonets will eat them.