Surprise in our Tank

[johnandpam]

We are new to this aquarium thing. Got a 5 month old setup in a 20gal with one chromis, two cleaner shrimp, one small feather duster, 8 snails, 15 very small hermit crabs. Just trying to get the hang of this hobby, got good test results for PH, amonia nitrites and battling with nitrates to keep low(many, many water changes). Now we have suddenly noticed something in my tank we hadn't before....It appears to be some type of Mussel on a piece of live rock. It is small about 1/2" and we did not put it there. Could it have been in or on the live rock when we set the tank up? We're guessing that the only reason it is alive at all is because we filter feed with zooplankton and phytoplankton for the worm. Do we keep it? It is open is that good or bad? Please help, we don't want to leave it in the tank if it is dead.

 

[mbbuna]

its hard to say if it alive or dead.i guess if you really want to fine out reach in and touch it and see if it closes.if it is alive i dont see any reason to remove it,one of the reasons i like this hobby so much is just for this,you never know what is going to pop up in your tank

 

[xdusty6920]

its probably florida rock and hitchikers of this sort are very common on that particular rock. they do filter feed and they arent harmfull to anything. the only down side to them is if they are not clear of junctions in your live rock, a quick contracting action can start an avalanche.
to keep down your nitrates try and syphon out any deterius (crud) you see collecting in cracks in your live rock or on the sand bed. also try and reduce feeding because theres a very high likely hood that overfeeding is whats causing this problem.