Zoanthids Closing

gt1968 · Mar 2, 2007

I have two tanks - 6 gallon and a 12 gallon Nano. I have noticed that my zoos are starting to close and fade away. For the life of me I have no idea why! The parameters in both tanks are as follows -

Salinity 1.025
9 DKH
Nitrate < 10
8.55 PH
Calcium 400

12 gallon lighting (2x24 watt 50/50 and 1x24 watt 03 actinic PC lights)
6 gallon lighting (1x18 watt 10K and 1x18 watt 03 actinic PC lights)

Photo period - 8 hours / day.

Does anyone have any ideas on what I have done wrong?

Azurel · Mar 2, 2007

Have you seen or noticed any thing irritating them?

organism · Mar 2, 2007

what kind of salt do you use, and do you know where your magnesium and strontium levels are at?

also, what are you using to measure salinity?

kappaknight · Mar 3, 2007

Are you experiencing temperature swings? Have you seen tiny nudi's on them?

gt1968 · Mar 3, 2007

I have not seen anything on them - in my 6... I have a quite a few tiny white star fish, but not in my 12.

pH - I usually look at it in the morning and at night. In the morning the pH is 8.25 and night (just before the lights go out it is 8.55).
Salinity - I use a Refract from Milwaukee Instruments - I also get my salt water premixed from my LFS.
Mag - Strong - I have no idea. I use Reef Complete for the Calcium, Stront and Mag supp.

Pufferpunk · Mar 3, 2007

Look really close, after lights out for an hour, w/a flashlight.

gt1968 · Mar 3, 2007

I just modified my earlier response. I do see quite a few white starfish - a couple are attached to the stems, but they don't appear to be doing anything. I might think that this is a problem, but I don't have them in my 12.

Pufferpunk · Mar 3, 2007

Did you look at Zoaid.com for ID?

gt1968 · Mar 3, 2007

I just found a terrible looking crab (all black body with yellow stripes and brown legs) attached to the bottom of one of my zoo rocks. I was able to get him out. Could this be the problem?

Pufferpunk · Mar 3, 2007

Check zoaid.com for a predator list. Sometimes an ugly black crab is just a crab.

na1paj · Mar 3, 2007

very possibly. some crabs are known to pull zoa polyps off rocks. but that may not be the reason for them to be closed.

sometimes zoanthids get "sick" and close up and die away. you'll know it when the polyps start to turn black. They can also develop fungus that kills them.

other than that, you just have to look closely at zoa preditors such as nudi, sundial snail, and asterina starfish. You can tell if it's preditors if part of the colony is closed up.

if all of it closed up, might be some sort of disease.

another possible reason is that the zoas are competing for the nutrients in the water. this happens when you don't do water changes...

do many 15% water changes for a week or two to see if it makes any difference.

gt1968 · Mar 3, 2007

I have hundreds of small tiny white stars all over the back of the tank as well as the rockwork. I have seen them once in a while between the zoo stalks or on them, but I figured these were harmless. They multiply like crazy! Could this be the problem? Most of these stars have 3... maybe 4 legs and are a dirty white color. If you think this is the problem in my 6... then how do I remove them or kill them since there are so many?

gt1968 · Mar 4, 2007

I am starting to think that these stars are Asterinas and have read that this could be the problem. I have so many I don't know the best way to get rid of them quickly. I am thinking of ordering a Harlequin Shrimp - what do you think?

ecotoxlady · Mar 4, 2007

I'd only go with a harlequin if you can afford to keep a supply of starfish for them to eat. From what I've heard, they go through starfish rather quickly. It might have been the crab causing the problem so don't jump to conclusions about the asterinas but I can say that I had them eat some of my zoas which was devastating. Thinning out the population seemed to have done the trick for me as most of the ones remaining seem to stay on the glass. Keep a close eye on the polyps that they sit on. If they are eating them those polyps will gradually disappear. Let us know what you find and definitely keep an eye out for nudibranchs because they sound like they might be the culprit and they stay dormant for most of the day and are best spotted at night with a flashlight.

gt1968 · Mar 4, 2007

How about fungus - I notice that there seems to be a white substance sloughing off on the stalks of many of my zoos?

ecotoxlady · Mar 4, 2007

How do the colonies smell? That can often be an indicator of what's going on.

gt1968 · Mar 4, 2007

I have not smelled them yet, but could too much light be an issue? This is a 6 gallon Nanocube with 1x18 watt 03 Actinic and 1x18 watt 10K running for 6 hours per day. How about supplements - I dose with Seachem Reef Complete 2 times per week (contains calcium, strontium and mag) and Reef Iodide every Sunday?

ecotoxlady · Mar 4, 2007

Without knowing your levels it's hard to say if you're under/over dosing. Lighting may be an issue if the zoas were under different lighting prior to this problem beginning. Often times an acclimation period and/or die-off occurs after a big change in lighting conditions. I would definitely check out how they smell though because if they smell foul I'd recommend doing a dip on them. I discussed the white fungus problem in the "Help" thread in zoa discussion so check that out to see if you have that problem. Please let us know what you discover and we'll all do whatever we can to help you save your zoas!