Please help with unhappy Zoanthids!!!!!!!!!

Kenyon · Jun 9, 2022

Long story short I have a 10 gallon zoa dominated nano with around 30 different varieties from low end to high end and about 6 varieties are suddenly acting unhappy, shriveling up, expelling guts, etc. The kicker is most of the high end varieties look great.. 25 percent of my zoanthid strains started to act weird about two weeks ago while the other 75 percent look great. From my experience I haven't had much luck with zoanthids once they become unhappy and start shrinking so I would like to figure out what going on before they go downhill fast.

Water parameters
Temp: 79 degrees
Salinity: 1.026 (Red Sea Salt)
calcium: 380
Magnesium: 1200
alk: 8.2
Ammonia: 0
ph: 8.2
nitrite: 0
Nitrate: 5ppm
Phosphate: 0

Lighting is one Ai Prime I will upload the settings but I haven't touched them. The tank is about two years old and is very simple, I run filter floss, carbon, wave maker, and do a weekly water change of 2 gallons.

I do have a very small population of digitate hydroids that gets controlled by a cleaner shrimp.. Although when they where very thick they only agitated my zoa's a bit but never seemed to kill them so I doubt they are the culprit. I have woke up in the middle of the night and inspected all the zoa's with a flash light and haven't seen any pest other than maybe 4-5 digitate hydroids that the cleaner shrimp missed.

The affected zoanthids seem to have part of their skirts folded inward and not smaller in size than normal. I have noted that the affected zoanthids have a small amount of the infamous white fuzz other reefers haven't been able to identify on the stalk of the zoa which may be some sort of infection but I have no idea. I have since dipped the affected zoa's multiple times in revive, H20, and iodine with little to no improvements. im pretty much out of ideas other than dosing vitamin C. Any help would be greatly appreciated!!!

vetteguy53081 · Jun 9, 2022

Kenyon said:
Long story short I have a 10 gallon zoa dominated nano with around 30 different varieties from low end to high end and about 6 varieties are suddenly acting unhappy, shriveling up, expelling guts, etc. The kicker is most of the high end varieties look great.. 25 percent of my zoanthid strains started to act weird about two weeks ago while the other 75 percent look great. From my experience I haven't had much luck with zoanthids once they become unhappy and start shrinking so I would like to figure out what going on before they go downhill fast.

Water parameters
Temp: 79 degrees
Salinity: 1.026 (Red Sea Salt)
calcium: 380
Magnesium: 1200
alk: 8.2
Ammonia: 0
ph: 8.2
nitrite: 0
Nitrate: 5ppm
Phosphate: 0

Lighting is one Ai Prime I will upload the settings but I haven't touched them. The tank is about two years old and is very simple, I run filter floss, carbon, wave maker, and do a weekly water change of 2 gallons.

I do have a very small population of digitate hydroids that gets controlled by a cleaner shrimp.. Although when they where very thick they only agitated my zoa's a bit but never seemed to kill them so I doubt they are the culprit. I have woke up in the middle of the night and inspected all the zoa's with a flash light and haven't seen any pest other than maybe 4-5 digitate hydroids that the cleaner shrimp missed.

The affected zoanthids seem to have part of their skirts folded inward and not smaller in size than normal. I have noted that the affected zoanthids have a small amount of the infamous white fuzz other reefers haven't been able to identify on the stalk of the zoa which may be some sort of infection but I have no idea. I have since dipped the affected zoa's multiple times in revive, H20, and iodine with little to no improvements. im pretty much out of ideas other than dosing vitamin C. Any help would be greatly appreciated!!!

Take salinity to 1.025. What test kits are you using ?
Test kits are a must to monitor tank. . .. Fish dont talk - Test kits DO and stay away from API kits.
I would highly suggest taking a water sample to a trusted LFS that does NOT use API kits and see what numbers/readings they come up with.
There are a number of factors why zoas close up. Some are water movement/flow as zoas do not require the consistent high flow conditions that SPS corals do. I would consider a moderate flow environment ideal but Zoanthids, like most corals, can adapt to low or high flow. In high flow, you will typically see polyps grow closer to the rock with shorter stalks. Another is lack of feeding and food as infrequent feeding and ultra low nutrient conditions can lead to entire colony meltdowns. Target feeding is not a requirement as Zoanthids are photosynthetic. I have found that target feeding Zoanthids always provides mixed results, when a food particle falls onto the polyps.

Back to parameters, good water quality is a must.
dKH: 8.0 - 11.0
Calcium: 400 - 440
Magnesium: 1300 - 1350
Iodide: Maintained via regular water changes or manually at small dosages
Temperature: 78-79 degrees
pH: 8.1-8.3
Phosphates: .04 - .06
Nitrates < 10

Asterina stars, little tiny tiny spiders and nudibranchs also will make them miserable to point of death as will aptasia, worms like spinoids or vermetid snails. A few things to look for. Hope this helps

Kenyon · Jun 9, 2022

Thanks for the reply!! I use hanna, Red Sea, and salifert test kits so I don't think I need to to have my water tested by a LFS. As I mentioned in my post I am pretty confident I don't have any pest as I check often in the middle of the night, all zoas have been super healthy for the past 6 m months and I haven't added anything or changed anything during that time frame so nothing bad was introduced.