Anyone know what can cause this ?

nybern · Apr 9, 2026

Had a torch coral with 4 heads one had flesh receding. Dipped in coral RX. Next day was gone. So I tool it out to frag off the dead head. When cutting the center was hollow. I cut all the heads and it was the same. What can do this ?

wasabi bean · Apr 9, 2026

I mean they could just grow like this, i have never really seen inside of a coral skeleton. You said it was receding could that be due to a lack of calcium which is very important for skeleton growth?

nybern · Apr 9, 2026

wasabi bean said:
I mean they could just grow like this, i have never really seen inside of a coral skeleton. You said it was receding could that be due to a lack of calcium which is very important for skeleton growth?

I don't think it's calcium I have many torches that a have fraged never seen this before.

Shirak · Apr 10, 2026

nybern said:
I don't think it's calcium I have many torches that a have fraged never seen this before.

Normal for the polyp to extend quite a bit down into the skeleton. If you frag healthy torches you won't see that cavity because you are not cutting into that part of the skeleton. If the polyp dies that cavity will remain.

nybern · Apr 10, 2026

Shirak said:
nybern said:

I don't think it's calcium I have many torches that a have fraged never seen this before.

Click to expand...

Normal for the polyp to extend quite a bit down into the skeleton. If you frag healthy torches you won't see that cavity because you are not cutting into that part of the skeleton. If the polyp dies that cavity will remain.

Makes sense thank you.

Timfish · Apr 10, 2026

Coral skeletons are porous and home to a host of organisms. The degree of porosity varies by species and variables affecting it's growth and calcification. These two Frogspawn skeletons are from the same mother colony and wiegh the same but grew in seperate systems. The larger one grew in a heavily fed ULNS sytem and the smaller denser skeleton grew in a system with moderate nitrate and PO4.