what are these?

[hackteck]

i made a post about 1 of these a while ago now they have spread and their covering 2-3 of my rocks and more growing in various placed anyone have any idea what they are exactly and if their good or bad?



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[hackteck]

another rock



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[Gti_Leo]

Kelp on Rock, Grape

looks a bit liek that

 

[hackteck]

nah thats not it maybe i will pull one off and a take a better close up shot

 

[hackteck]

well after about an hour or two if googling i think its branching corralline

 

[Emelinda76]

well after about an hour or two if googling i think its branching corralline

Looks cool though

 

[brian242pa]

it looks like a fan but short an stubby lol, i had three of these but the never spread like yours