strange things

Question
QUESTION: I have a new 30 gallon salt water tank...I have over the coarse of the last few months discovered bits of rock which appeared to have been broken off of the live rock.. Ihave disovered a dark gray looking crab in the live rock..I want o know if it is dangerous to my fish...I also found a black fuzzy looking caterpillar like thing.It is very small but moving. What do you think it is?

ANSWER: Hello Tyra, (or is it tyracloset?)

You are the first person I have heard call a tank new that has been setup for at least a 'few months'.

Most folks i know have that tank already setup with tons of corals in it..

But you are right, that is a relatively new tank.

As for bits of rock???

How big are these bits? What fish do you have in there?  What other critters do you have?  There are some critters that bit rock, but they do it for different reasons, most do it to digest the algaes that are on the rock, the end up pooping out the waste rock and it accumulates in piles around the tank where the flow my push them.

I suck those piles out every other month or so,.  (I have a larger tank)  I actually use a 'shop vac' and put the hose in the water, and have it right next to the pile, then turn on the switch to the shop vac and suck out the 'detritus' and a few gallons of water.

This avoids stirring up the poop into the water column then only getting a diluted water taken out when i do the wter change.


Other fish, like triggers might bite rock to keep thier teeth sharp or to wear thier teeth down, as evolution has taught them...

I have learned to not like crabs.  And like i suggested to others in prior messages, if you didnt buy it, then it shouldnt be in your tank.  or in other words, you got MORE Then you bargained for.

If you can get a picture or describe it better, i may try to ide it for you and maybe it isnt a bad crab, (BTW most crabs arent bad)

some crabs get a bad rap, as folks will see them on top of and devouring thier favorite fish. BUT in reality, the poor fish died for some reason, and the crab is just doing what it is supposed to, and that is clean up...

And the black fuzzy thing... Hmmm,. I would still ned more information.  If i were to take a wild ass guess, I might suggest looking up 'Scutus' and or black scutus, or black limpet




But that would be a big time WAG


Anyways, please let me know more info or how things work out for you


Bill



---------- FOLLOW-UP ----------

QUESTION: Hi,
Thanks Bill.. Unfortunately the crab is in a hole in the rock and the only way I can see it is by shining a flashlight into the whole... I have tried to catch it at night at which time I observed a piece of rock being pushed up out of the hole.. But the crab will not come all the way out..As for the fuzzy worm..It hides and I have only seen it twice when I am on my way out..When I am actually looking for it, It is nowhere to be found...I took a look at the black scutus and this is not it.. the thing in my tank is almost caterpillar like and it is sort of fuzzy..I will have to see if I can find it again and get a picture.  We tried to extricate the crab..no such luck...

Answer
Hello Tyra,

Try using a smooth bottle, and place a small piece of fish or bait into the bottom and angle the glass so that a crab could not climb out, once it gets in...

It doesnt have to be 'steep' but as long as it is slippery enough, then the crab wont get out...

this will work with worms also, but, it usually is a slightly steeper angle...

And yes, a picture will help in id'ing the your fuzzy caterpillar thingy...

hehehe


b