Tongue Cora (loosing its zooxanthellae)

[cmay]

I recently purchased a Tongue Coral (Polyphyllia talpina) from my LFS.

On first inspection the coral showed good colour including the the underside, he was in a small display tank under a 30w 10k T5 displaying a few polyps.

After about two weeks I noticed the underside looked as if the coral was loosing its zooxanthellae and the tissues was falling off.

The underside is now white, i've never seen more than 20% of the polyps out during the day, however at night, lights off he balloons up clearing any sand that has fallen on him and displays about 80% poylops.

The only light on after the tank lights go out is my dining room light.

I have 250W 10k MH, my other LPS and SPS seem to be doing well, water quality is within correct parameters.

Does any one have any suggestion, I was wondering if he was not use to the light, but im not sure how this would cause bleaching on the underside only.

Thanks

[Amphibious]

Originally Posted by cmay

After about two weeks I noticed the underside looked as if the coral was loosing its zooxanthellae and the tissues was falling off.

I'm curious, where do you have the coral placed in the aquarium?

Also, you mentioned the light source at the LFS was 30w 10K T5. Is this correct?

Dick

[cmay]

Thanks dick for the reply.

The display tank was a very small Nano type tank, the light was a double bent T5.

I was quite surprised myself, I kind of felt sorry for the coral, another reason I picked him.

I've place the coral on my sand bed in moderate flow directly under main source of light for a week, I've also tried a slightly darker end of the tank still on the sand bed, as recomended on articles i've read.

[CarmieJo]

How deep is your tank?

[lReef lKeeper]

the "double bent" T5 sounds like a PC light to me, jumping from PC to metal halide can be very stressful on the coral. i would leave it alone for a while and see how it responds.

[Amphibious]

I was wondering that myself. You might consider placing a light reducing barrier above the coral on top of the tank for a few days.

Dick

[lReef lKeeper]

Originally Posted by Amphibious

I was wondering that myself. You might consider placing a light reducing barrier above the coral on top of the tank for a few days.

Dick

i would try at least 2 layers of fiberglass or vinyl screen from HD or lowes, even if it is just above the section of the tank that the tongue coral is in. i bet it is a lighting issue, coming from PCs to MHs.

[cmay]

My tank is 2 feet deep, The LFS sold the same light, if I remember correctly it was only 30W.

I thought my light system was a big jump, especially as the coral seems to come to life when my lights are off and my dinning room light is on.

I’m really concern I may loose him, kind of makes me feel guilty

[cmay]

Originally Posted by lReef lKeeper

i would try at least 2 layers of fiberglass or vinyl screen from HD or lowes, even if it is just above the section of the tank that the tongue coral is in. i bet it is a lighting issue, coming from PCs to MHs.

I will see if i can sort out some form of light barrier, i may try and place a 30w T5 over my sump and place him there.

Do you think I should add any suplements

[lReef lKeeper]

i would not supplement unless you have test kits to test for what you are adding. i dont think it is a deficiency of anything, just needs to be acclimated to the high output lights.

[cmay]

Thanks for all the advice, I will find a way to reduce the light and see if this helps, hopefully I can make him feel happy again.

[cmay]

Originally Posted by lReef lKeeper

i would try at least 2 layers of fiberglass or vinyl screen from HD or lowes, even if it is just above the section of the tank that the tongue coral is in. i bet it is a lighting issue, coming from PCs to MHs.

I've managed to place the coral under my big Sarcophyton which allows for the tongue coral to sit in the shade without fear of them touching each other.

Within an hour the tongue coral ballooned with nearly all polyps showing and even the colour seemed to look more vivid.

So I'm hoping all your advice pays off, I will let you know the outcome.

Thanks again.

[lReef lKeeper]

you got it, thats why we are here.