OK, maybe not a bath, but a shave? I have a clam that has two things growing on its shell. A small patch of GSP that started because I was a bit remiss in keeping it trimmed back. The second is some hair algae tha sadly is growing at incredible rate on th poor guy.
The GSP doesn't seem to bother it at all. Been ther for quite some time, touching the mantle with no noticeable effect. But, I am worried about th hair algae, cuz a) it's in my tank! (more on that later) but also, b) i worry that th algae can block light need by the zooxanthellae. So, I have been pulling it off. Of course, you can't pull it all off...
Were I to gve th clam(shell) a scrubbing, would I do more harm than good? I am thinking stainless steel wire brush? The mantle MOSTLY retracts when it is nervous, so I would need to be careful around that... I definitely don't want to harm it.
If it's a small Tridacna I wouldn't mess with it (they're just too sensitive). Rather address the cause of the algae and the nuisance will go away.
Based on the thread title I'm assuming it's a larger clam, and further assuming it a Tridacna. If my assumptions are correct and the clam is >4 inches, then some scrubbing should be fine (I have done it to my clams in the past). I would avoid metal bristles. A toothbrush works well on most algae species. Depending on the type of hair algae you may be able to just pull it off with your fingers. Definitely exercise caution when working near the mantle as well as the byssal opening. Lastly, only clean a little bit of the shell at a time in an effort to minimize stress.
Good luck and keep us posted... some before and after pictures would be cool to see.
Hey there. A very quick way to remove hair algae without scrubbing the crap out of the clam is to take a toothbrush, dip in Hydrogen Peroxide and scrub the hair algae. It just falls apart and dies, I rinse things off in some tankwater before putting it back, but it works like a charm on live rock and every other time I have tried it.