I have never seen a coraline algae this dark.

[4mocajuns]

I haven't been at this long but have been looking for another tank with this same growth. Any of you have it? :notsure:

 

[salty cheese]

The "coraline" is most likely a sponge and the star is a asterina starfish. :happyfish

 

[ophiura]

Originally Posted by Salty Cheese
The "coraline" is most likely a sponge and the star is a asterina starfish. :happyfish

 

[coachklm]

i never have either but i know i never will.... they are correct on your sponge...filter feeder good and the asterina stars well...they are just stars...

 

[chipmaker]

The dark is a encrusting sponge just llike others have stated. Its beneficial, and helps filter out food etc from the water. Its a filter feeder......The star is a comopn asterina, or as some folks call em a parasite star. Some say they eat coraline, and corals others say they are fine. Personally I have never had a problem with them. Thye are quite prolific, but easy to control, and if things get too far out of hand buy a harlequin shrimp as they love to eat those stars.. There is somethng like 117 different stars in the asterina family, and just like bristle worms, there is actually only 2 or so thats not desireable, and they are not commonly found as hitch hikers anyhow, but folks usually windup pulling and flushing them. Watch them and see what they do or don;t do, before making any decisions to eliminate them. Odds are they will be just fine.