Little White Discs

[DKJONES]

I have little (maximumum 1/8th inch) oval-shaped, white discs that have begun appearing all over my 24 gallon nano-cube reef tank. The started on the live rocks and now are appearing on the back and sides, even power pump cords. They don't seem to move, and algae will even grow over them. None of the inhabitants seem to eat them - if they do, the population is definitely keeping up and surpassing demand! They don't appear to start small and grow - new ones suddenly just appear. The seem to like dark areas as well as lighted ones. I must have hundreds by now. The rest of the tank is stable and doing well. Any ideas on what they are? Are they harmful or beneficial? If necessary, how do I get rid of them?

[Arctic Fox]

If what it sounds like, is what I am thinking they might be worms.

I don't remember what they're called exactly, but they're similar to minature feather dusters and instead of growing their tube in a straight line they curl it around like a snail shell. To the best of my knowledge they're fine and it means you have a healthy tank.

[DKJONES]

Maybe. The are quite flat and don't appear to have any sort of opening or texture. To give an idea of how fast the multiply, what was one in the corner of my tank about a three weeks ago, is now about ten. They are everywhere! I've poked one or two with a sharp instrument and they do crush with some pressure, but nothing else appears - no insides per se. They are about the size of this typed letter "o". They aren't unsightly yet - I just don't want them totally taking over!

[flip_3_6_0]

Could it be snail eggs of some sort?

[DKJONES]

I had considered that, but some have been there for quite a few weeks. Some have been covered with some green algae, but are still visible. I don't think they are eggs unless they are laid in a packet of sorts.

[zhenya]

Give this article a read over, it may answer your questions better than any of us can.

FWIW, in a newly established tanks, this happens from time to time and there is a explosion of Foraminiferans but most of the time the numbers diminish fairly quickly, so I wouldn't worry about this.

[DKJONES]

I think you got it! Very interesting! From the article it sounds like these creatures live predominantly in the sand. I haven't noticed any there (I will certainly look) but the are attached to almost everything else. Sounds like I shouldn't be too alarmed. Thanks!

[zhenya]

I think you got it! Very interesting! From the article it sounds like these creatures live predominantly in the sand. I haven't noticed any there (I will certainly look) but the are attached to almost everything else. Sounds like I shouldn't be too alarmed. Thanks!

Yes, it seems that they predominantly occupy sand beds but sometimes they are found on other substrates as well. FWIW, I had this occur in both of my tanks when they were first set up. After few month they all but disappeared.
Pitty,I thought, I love to have as much diversity as possible in my aquariums.

[ricksreef]

just to give another possibility, do you have any nerite snails,
if so, sounds like they could be eggs.

[DKJONES]

I do have some of those snails! What's in the picture also looks very similar to what I have. If they are eggs, I haven't seen any hatch or any signs of baby snails. How long would it take for them to hatch? Would the babies be in a larval form of some kind (and likely eaten) or are they tiny snails?

[zhenya]

Here's what the eggs look like under that proteinaceous membrane...



As far as having babies, I doubt this very much becouse they do have prolonged larval stage in their developement. The best way to see any of the babies would be to relocate snail in a separate jars and let them lay eggs there, remove snails after that. I've forgotten how long it takes for the eggs to hatch but you would have to feed the larvae with some live phytoplankton, preferably various types and hope for the best. I had some copies of the manual on to how to hatch and raise snail larvae but cannot find it at the moment.