What Is This Growing On My Live Rock???

Marco S · May 26, 2019

I have a 45 Gallon QT Tank that has been up and running for about 4 months now. It is the final stage in my QT and has never had any meds in it so I have about 40 lbs of live rock in it. Over the months it has grown a lot of coralline algae all over the rock and the back of the tank. I way overfeed this tank as this is the last step before going into my DT and I want the fish fat and healthy before having to fight for food.

I currently have a Harlequin Tusk, 2 PJ Cardinals and 1 Blue/Green Chromis and I feed them a ton or Mysis, Krill, Clams and the occasional jumbo shrimp. I also monitor the Nitrates and do frequent water changes so it never goes above 20 ppm. Salinity is at 1.025 and temp is a steady 78. Not sure about any other parameters since this is just fish and no coral.

Today I noticed a bunch of white stuff on the rocks that has appeared overnight, (OK maybe over a couple days) and I don't know what it is. If someone knows what it is, please let me know and whether I need to take action or just leave it alone. This tank will probably only be used for another couple of weeks or so then it is getting converted to a freshwater planted tank so I don't really care about the long run, but am concerned if it is something that I need to take care of immediately.

Here are a few pics:

Thanks in advance for any help.

RJinPV · May 26, 2019

It's hard to tell from the pictures but could it be coralline algae dieback exposing the bare rocks? Or is it growing over whatever was there?

Marco S · May 27, 2019

RJinPV said:
It's hard to tell from the pictures but could it be coralline algae dieback exposing the bare rocks? Or is it growing over whatever was there?

It is growing over the rock, not exposing the bare rock. Also, the big purple rock in the middle is the Reef Rock dry rock and besides a few white spots where little pieces got chipped off while transporting and handling, it has no growth on it at all. Only the live rock had this and in some places it looks like tiny strands of string weaving in and out of the rock. I will try to get a better picture later today.

shornik · May 27, 2019

Marco S said:
It is growing over the rock, not exposing the bare rock. Also, the big purple rock in the middle is the Reef Rock dry rock and besides a few white spots where little pieces got chipped off while transporting and handling, it has no growth on it at all. Only the live rock had this and in some places it looks like tiny strands of string weaving in and out of the rock. I will try to get a better picture later today.

It looks like bacterial mats to me, you can blow them off with a baster or better suck them out. If that's what it is, it probably means some of your parameters may be out of whack.

Reefing Madness · May 27, 2019

Looks like a very bad case of Cyano. That needs to be cleaned up quickly or like you see now, its going to take completely over your tank. Use a small brush, wave it off with hand, get more flow in the tank. What you see on your tank walls and rocks is not coralline algae, the white you see is in fact places where the cyano has been removed and you see the real rock now. The whole tank will look like that when your done cleaning that stuff off.

Marco S · May 27, 2019

shornik said:
It looks like bacterial mats to me, you can blow them off with a baster or better suck them out. If that's what it is, it probably means some of your parameters may be out of whack.

I will see if I can suck it up when I do a water change later tonight. If it is bacterial mats, will it negatively affect the fish in any way that I should be concerned about?

Reefing Madness · May 27, 2019

Its just nasty stuff, not gonna kill your fish, just unsightly. You can remove it with ease, although it may come back quickly, just will have to stay on it.

Marco S · May 27, 2019

Reefing Madness said:
Looks like a very bad case of Cyano. That needs to be cleaned up quickly or like you see now, its going to take completely over your tank. Use a small brush, wave it off with hand, get more flow in the tank. What you see on your tank walls and rocks is not coralline algae, the white you see is in fact places where the cyano has been removed and you see the real rock now. The whole tank will look like that when your done cleaning that stuff off.

I will do my research later on Cyano, but is it something I need to be concerned about with fish only and the fact that it will only be used for another 2 to 3 weeks before it will be torn down, scrubbed out and used as a freshwater tank?

Marco S · May 27, 2019

Reefing Madness said:
Its just nasty stuff, not gonna kill your fish, just unsightly. You can remove it with ease, although it may come back quickly, just will have to stay on it.

You typed that quicker than I typed the question you just answered. Lol

Reefing Madness · May 27, 2019

Reefing Madness said:
Its just nasty stuff, not gonna kill your fish, just unsightly. You can remove it with ease, although it may come back quickly, just will have to stay on it.

Its not gonna harm your fish

jeffchapok · May 27, 2019

I agree that other than that one purplish rock, it looks like cyano rather than coraline. Cutting back on my lighting schedule, especially white, and adding a UV sterilizer cleared mine up in a couple of weeks. Suck out as much as you can each day too.

vetteguy53081 · May 27, 2019

Youre past the new tank uglies and Cyano and slime have been established.
Having a net and siphon available, take a turkey baster and gently blow material loose and net and siphon suspended matter right away. Then do a water change and reduce amount of time lights are on. There is a product known as Chemi clean available which will help get rid of this. Also have your water tested for phosphate which is often the cause when high in numbers

curly0427 · Sep 3, 2020

Can anyone help me identify the brown branch like cluster growing on my live rock?

vetteguy53081 · Sep 3, 2020

cluster dusters

curly0427 · Sep 3, 2020

vetteguy53081 said:
cluster dusters

A good thing to keep?

vetteguy53081 · Sep 3, 2020

curly0427 said:
A good thing to keep?

They can get out of control but harmless

curly0427 · Oct 3, 2020

Anyone have any idea what this is?

curly0427 · Oct 3, 2020

Mikedawg · Oct 3, 2020

Looks like cyano to me

vetteguy53081 · Oct 3, 2020

Cyano. May be developing into dino but Dont assume yet.
Test your phosphate level and also . . . are you usin RO water or tap water from the sink?
Siphon this matter up and blow rest loose with a turkey baster and siphon or net the loose matter. reduce white light intensity slightly and see if and how soon it returns.