They are filter feeding sponges and will continue to spread. They are harmless and stationaryHi! Can anyone help me identify this new growth? They're like green spots with tubes and all over my rock throughout the tank. It's pretty cool looking, but I don't know if it's a good or bad sign or if it's healthy to keep. I have posted a couple of pics. Thank you in advance!
Generally hitchhiker on live rock which favors low light and low flow areas
A very select few sponges could irritate corals due to toxins they produce (these sponges compete chemically with corals), but very few sponges seem to do this. Most sponges will happily grow along the skeleton/base of corals without bothering the corals or trying to grow over them at all (sponges generally are so harmless that even the more invasive ones can generally literally grow over the top of corals, and - as long as the coral is getting enough light still - they don't harm the corals at all even when growing over them).
They can spread and take over a coral in time if thats what youre wondering. I have removed sponge off my elegance as I want nothing on its wall. I have one recently discovered tunicate I found over the weekend allowed but generally remove sponges as I find them as they get too close to my coral
