What could cause this, should I worry?

[Animal-Chin]

Ok, the history...

125 gallon tank gets velvet and wipes out fish.....

I let the tank go fallow for 8 weeks. Add quaranteened fish to tank (4 of them over a month period). Less than a month after the last fish was added, velvet is back and kills 3 of them....

So thats the only changes in my tank, my bio load went from no fish for 2 months to 4 where I was over feeding to get them nice and strong but it didnt matter the velvet was still there...


Now on to the issue. For the last week, since the recent die off of fish that I was able to remove before they died so there is no rot issue, my coral are acting up. At about 9 pm every night my bubble coral, my forest fire digitata, my duncan and my rbta all close right up. Its like clock work, every night at the same time they all recede right into their shell or in the anemone's case just suck all tenticles in. Now all the other coral (LPS, SPS, Zoa's...) remain perfect, its just this select few but its the same ones every night.

Why would this be? Is the system shocked due to the lack of fish/feeding again? Is this jsut an adjsutment period or is something causing this?

Nitrate, phosphate and amonia all at 0. My filtration is strong especially for such a small bio load.

Cal 420
Alk 9
Mg 1300


Thoughts?

 

[Sniperhank]

Though it sounds to me like something is going on in your system in regards to fish, though I wouldn't be able to pin point that issue, I wouldn't be too concerned about the behavior of the bubble coral, anemone...I see similar out of them in my tank as I am approaching lights out. There has to be something in common with those coral/anemone that happens at that time, be it a change in flow or something that occurs at 9pm that isn't effecting everything else.

 

[Animal-Chin]

oh the fish is a no brainer, its velvet for sure. That I understand. Now I have a 125 gallon with one little wrasse in it (if someone can advise me on how to get this trouble maker out I'd appreciate it). Its the wierd behavour of the coral since the fish are gone that's my question. I'm wondering if there is some sort of gas happening or something. Maybe not adding any food/poop to the water changes something in the tank? Its just sorta weird...

 

[Sniperhank]

Could be related to not having the food/poop to capture, but why 9pm? They are always gone, not just at 9pm. There is something related to that time that is the reason.
I know at lights out in my tank, the flow pattern changes to a constant flow pattern and would cause it there. Breaking down what happens before and during this time will lead you towards the cause.

 

[Animal-Chin]

Ya but what could it be? I too have pumps that ramp down after the lights go out but my lights go out at 10:30. Nothing significant happens at 9:00. My fuge light comes on around 11:00. 9:00 is nothing. So weird.

 

[Rockster2]

It's odd for the RBAs to shut down every night but it is otherwise very common behavior for most corals to withdraw at night, especially Lps and soft corals. I wouldn't worry about as long as they continue to open and extend in the day while your lights are on.


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[Animal-Chin]

They all do it 1.5 hours before the lights go off. Thats the thing, the lights are still a shining...

 

[Sniperhank]

Got used to the cycle and prepping for it.


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[navaljonf]

It's odd for the RBAs to shut down every night but it is otherwise very common behavior for most corals to withdraw at night, especially Lps and soft corals. I wouldn't worry about as long as they continue to open and extend in the day while your lights are on.


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My RBTA shrinks to poop everyday at the same exact time. I wouldn't be concerned unless they aren't looking good when open.


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