Zoas

[slinkyslink]

In my tank I have a zoa coloney and every now and again the produce like a stringy substance from there mouths that is several inches in lenth. Why do they do this?

[danwin]

mine do it also mate, is it a browny colour? The only thing i can put it down to is maybe they are just getting rid of their waste as we do if, you know wat i mean!!!!!! if its not then i also would like the answer to the question.:D DAN

[moorish]

could be the same as anemones do,they expell a brown waste from their mouths every so often,off the food they ingest.derek

[JAYJT29]

In my nano i have witnessed this once with both my zoa colonys, this wass when i changed a bulb. Have you cahnged any bulbs prior to this happening?

[berns]

zoas gain nourishment via the light by photosynth their internal cells (like leaves on a tree), then once the cells are depleted of nourishment they expell them = brown stringy expulsions, they start this process again with newly produced cells. so every now and then you will see this activaty.

also its quite common for them to expell after being moved and placed under different lighting, so any newly added stock to your tank will often instigate an expulsion.

[MR Teee]

The cells are called zooxanthallae, as Berns has said it iss how the produce food.

These can be expelled as part of a normal process, Again as described or above.

Or can be expelled as a result of a shock event, ie light bulb change, major parameter shift. This reason is not so good, and will put the coral in a weakened state until the organism regain their numbers.