What is this in my sandbed?

[marine novice]

This may not be the right thread for this but it's the closest I could find to the issue we are having. My wife and I are very new to saltwater aquariums and are stumped as to what's going on or how to fix it. The water has a green tint to it and there is this mold looking stuff covering the whole sandy bottom of the tank. There also appears to be tiny almost dust like "bugs" living in this stuff. Our two clowns seem to be fine even though they have stayed in the same corner of the tank since we got them, our cleaner shrimp are doing fine as well but our thorny Red Sea star looks like the ends of two of its arms are rotting. I thought he was dead and took him out but he was still moving. Please help!!!


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[Bectan01]

How old is the tank? What kind of filtration/flow do you have?


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[carey]

Yep, I have the same questions, how old is the tank and how long has it been cycled? That could just be diatoms which is a completely normal thing to see in a newer tank. The bugs are most likely "pods" which are a good thing and dont harm anything at all, they actually add to the ecosystem of the tank.
As for the clowns, well, every pair I have had always stayed pretty much to one corner and only ventured out once in awhile, like to chase food. lol
And the sea star, hate to tell you but it doesnt sound good. Thats how they look when they are dying, they kinda disingrate from the legs tips upwards. Stars dont do very well as a whole in home aquaria so it's not something you may have done or not done, just how they are. I tend to stay away from the starfish except for serpent stars which are pretty neat and have a better chance at survival.