Unidentified Stationary Organisms

[R7-12]

Hi everyone,

I'm new here and not sure if this is the appropriate place to post this question. Please let me know if I should move this post elsewhere.

After 6 weeks of cycling my new tank with cured rock I noticed a few small white specs appearing on all the tank and sump glass but nowhere else. I know these aren't the common spiral feather dusters because of their shape. Anyway, after two weeks many more have appeared and some have grown to 1/4 to 1/2 inch. They are everywhere including the sides of my skimmer and do not move.

Tank inhabitants include 1 Perc, a few hermit crabs, 9 nassarius snails, and 5 or 6 small rock crabs. We have not yet placed any corals in the tank. Water parameters are all good now since the ammonia dropped.

I have taken a few pics and cropped them down to keep the file size manageable. You'll notice on the #12 shot there is a small circle with what appears to be small eggs in it.

If anyone has any helpful info on what these are and if they are OK, I would be very grateful.

Thanks,
R7-12

[Der_Iron_Chef]

A type of sponge (Scypha), sometimes referred to as a "pineapple sponge" I think. Harmless. :)

[Myka]

^ He got it. They are good, they help to filter your water for you. A sign that your tank is starting to "get comfortable", and that's good. :)

5 or 6 small rock crabs.

I'd like to know more about these "Rock" crabs. I'm suspicious. Did you add them yourself, or were they hitchhikers? Do you have any pics?

[R7-12]

Thank you for your replies and comments.

I suspected they were a type of filter so I left them alone until that was confirmed. The only problem is they are everywhere and that makes my whole system look like it's been infested.

Do you think they will become reduced through competition for nutrients? Should I try scraping some of them off the glass? Would it be recommended to start using RowaPhos and perhaps carbon at this point?

Myka - The rock crabs in the tank came with a few pieces of rock but I don't consider them to be a problem for now. When I start placing zoas and mushrooms in the tank I will separate the rocks with crabs from the rest of the tank with a short piece of glass in the sand that will act as a wall.

They are light coloured with a brown or black area on their body. I thought keeping them will help clean up some of the uneaten food.

I don't have any pics of them but I could try to take some.

Thanks again for your answering my questions.

R7-12

[Myka]

Most hitchhiker crabs are bad...they will either eat corals or fish. What I'm picturing in my head of your description of the divider won't work. I'd pull them all out now, and get a positive ID. Nothing with claws is allowed in my tanks (hermits, crabs, lobsters), with the exception of Peppermint and Cleaner shrimp. Shrimp are really good for eating uneaten food, and won't cause trouble (other than maybe the Coral Banded shrimp).

Personally, I run RowaPhos (in a reactor now that I have one) as soon as the cycle is over.

You can clean your glass of the sponges. I keep my glass all nice n clean. :D Don't worry about them being on the rocks or anything, they will die down once your tank establishes itself better.

[R7-12]

Hi Myka,

I was planning on having only two or three small/medium sized rocks on one side of the tank separated by a short piece of glass running from front to back, to prevent the crabs from gaining access to the rest of the tank.

If the crabs show any signs of getting over the wall, I will remove them.

Do you think scraping off lots of the scypha sponges will result in an ammonia spike, or will they stay alive for awhile and then die off slowly?

R7-12

[Myka]

Hmmm...well why would you want to do that to your tank? Kinda wrecks the look I would think. I don't think they'd get over a full divider.

I don't think you'll have any troubles with ammonia or nitrite by scraping the sponges. Many of them will still live, and just slowly die off. If you're worried, just scrape one pane per week.

I just noticed your comment about those eggs in the picture. They are likely snail eggs of some sort, not from the sponges.

[R7-12]

The tank will be mainly for zoas and shrooms - basically a small frag tank so it won't matter if there's a short glass barrier in it.

Having said that, I think my wife and I will do a bit of crab fishing tonight anyway. Having no crabs at all will just be better all around I suppose.

Thanks for identifying the eggs as possibly snail eggs. Now that I know what to look for, I won't scrape them off next time I see them.

R7-12