Are these tunicate or sponges or something else I’m not sure and are they good or bad and if their bad what should I do to get rid of them

[yellow tang lover]

 

[yellow tang lover]

oh and I forgot to say I have had these for a couple months

 

[JoJosReef]

Pic isn't too clear, but looks like pineapple sponge. Good guys to have. They will help with filtering the water.

 

[vetteguy53081]

These are pineapple sponges which can be from new rock, new sand, from tap water if used and expired or leaking Di Resin cartridges.
These are short lived and will dissipate as silicates reduce. You can peel them off with the edge of a credit card into a net if they are too many
They are not harmful and cherish algae if they get any and filter feed on algae- not filtering water which tunicates would do

 

[yellow tang lover]

These are pineapple sponges which can be from new rock, new sand, from tap water if used and expired or leaking Di Resin cartridges.
These are short lived and will dissipate as silicates reduce. You can peel them off with the edge of a credit card into a net if they are too many
They are not harmful and cherish algae if they get any and filter feed on algae- not filtering water which tunicates would do

Thank you my tank is 2 years old so no new rock or sand or tap water so probably time to replace my Di resin