Random Zoa Die Off

dettmerr · Dec 10, 2023

Hey all,

Reaching out because I’m at a loss for what might be causing this issue. I’ve been successful in keeping zoas, including stratospheres, great owls, GMK, LSOH, and more. But suddenly, in the past 2 weeks, I started to have a random die off. The zoa appears to invert it self, which then leads to a black covering and ultimately the polyp dies (picture of current process happening). I’ve had colonies die off, but if I frag a polyp, it has a 50/50 chance of surviving. Parameters have not suddenly changed and have been consistent for months, spreadsheet attached below. Tank has been up for about a year.

I recently found a thread of zoa enthusiasts that dose chemiclean monthly to help prevent odd bacterial infections. Which I did a dose, and it seems to not have done much of anything.

I perform weekly water changes, occasionally spot feed with coral frenzy. I have flow of 2 MP10’s and upgraded return in a WB20. Lighting is a G4 XR15 Pro. Zoas not in direct flow and racks blown off to prevent detritus frequently.

If anyone has any ideas or potential resolutions, I would be willing to listen to anything. I have lost my stratosphere colony, multiple death star frags, exo frags, and more than I can count…

Aside from the zoa die off, I have thankfully not had any issues with any other coral. I will upload FTS. Plenty of success with torches, chalices, acans, and Gonis. Until recently, zoas were out of control on growth then suddenly stunted with this problem. Have tried to iodine dip when the problem arose, but that led to a quicker melting process.

Thank you for your time and for everything!

VintageReefer · Dec 10, 2023

Can we get a better pic of the black covering a zoa? Maybe in white light ?

Cichlid Dad · Dec 10, 2023

Just throwing it out there, I see mag swings, I assume first column is nitrate, I Run mine @ 10- 25 with phos around .1 and pH not shown on your spreadsheet. Maybe others will way in on this. Once I started keeping my tank rock steady it took off and no longer had mad zoa's

littlebigreef · Dec 10, 2023

Whether it’s bacterial or protozoan I can’t tell you. However, as a zoa collector/grower I used to deal with this regularly before I started QTing zoas.

Chemi clean is the right answer here but you should dip instead of treating system wide. It’s my experience that regular system wide dosing can diminish chemiclean’s effectiveness. Sometimes it’s absolutely necessary to dose system-wide but only as a preventative measure, if you catch it early enough you can just dip affected frags.

Chemiclean is pretty mild. 2 scoops to 8oz water for 15-20mins. If you can add a bubbler and a few drops of lugols it helps tremendously. 3-4 days on, 1-2 days off and repeat at least a second round even after you start to see improvement.

This and ‘the shrivel’ are the two most encountered zoa issues. You can also add a scoop of metroplex to the above dip, and it should cover treatment for both issues.

Feel free to shoot me a DM if you want. Zoas are my favorite coral because they give you decent leeway to save them- and that’s a nice rack you got there lol.