Looks like dead spots starting

painter1982

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What would cause these dead looking spots and how do I proceed? It’s the only coral like this. Right at the base. During the day it almost looks like some polyps still alive but I’m not sure. This is my fastest growing coral. It just started within a week.




 
What would cause these dead looking spots and how do I proceed? It’s the only coral like this. Right at the base. During the day it almost looks like some polyps still alive but I’m not sure. This is my fastest growing coral. It just started within a week.




 
Tank parameters
Salinity 1.025
Temp 77.8
Alk 9.1
Phos .02 to .07
Nitrate 4 to 9
Calcium 420 to 440
Mag 1350
 
20250913_215423_10254053-0D86-4A9F-85C2-23E8DB61E81D.png
 
Montipora? I had similar issues on my Montis several years ago and found Montipora eating nudibranches.

Is the frag removable?
 
Montipora? I had similar issues on my Montis several years ago and found Montipora eating nudibranches.

Is the frag removable?
Yes, montipora. It’s epoxied down. I can see some kind of pods crawling on the spot at night. They take off running when I shine a light. How small are the nudibranches? I don’t see any of those. A plating monti has an edge white too. I just don’t see any kind of predators on them. All the acros look fine.
 
Monti Eating Nudis are smallish. Mine were white with blue on their backs. They were barely visible and only after dark.
 
Monti Eating Nudis are smallish. Mine were white with blue on their backs. They were barely visible and only after dark.
I’ll keep an eye out for them. I’ve only seen pods crawling on the dead spots. Never knew I had so many!
 
What would cause these dead looking spots and how do I proceed? It’s the only coral like this. Right at the base. During the day it almost looks like some polyps still alive but I’m not sure. This is my fastest growing coral. It just started within a week.
This could do it.

Screenshot_20250915-160900.png

This could easily be a zero on some test kits.
How long has it been this low?

Running 9.1 alk, you need more nutrients.
There is a coralation.
Also, do you know your par?

Pods and hermits/snails are after the free lunch. It's what "clean up crew" does, normal.
 
Last edited:
This could do it.

Screenshot_20250915-160900.png

This could easily be a zero on some test kits.
How long has it been this low?

Running 9.1 alk, you need more nutrients.
There is a coralation.
Also, do you know your par?

Pods and hermits/snails are after the free lunch. It's what "clean up crew" does, normal.
It could be but 9.1 is right on th cusp of needing phosphates for Acros - being a Digitata (at least that's what the picture looks like) and not being the growth tips I'm less inclined to see low phosphates as the most likely cause.

I could for sure be wrong there, but the pattern of STN looks more like something's munching starting from the edges, not the tips?

Low phosphates/high alkalinity usually starts at the tips of branches of Acros - at least in my experience.
 
It could be but 9.1 is right on th cusp of needing phosphates for Acros - being a Digitata (at least that's what the picture looks like) and not being the growth tips I'm less inclined to see low phosphates as the most likely cause.

I could for sure be wrong there, but the pattern of STN looks more like something's munching starting from the edges, not the tips?

Low phosphates/high alkalinity usually starts at the tips of branches of Acros - at least in my experience.
For sure burnt tips on acros and other up growing colonies. This looks like a plating type Monti or a hybrid, I could be wrong.
I would not rule out my hypothesis so early.

OP, have you actually seen evidence of pests? I'm sure you will look now!
 
It could be but 9.1 is right on th cusp of needing phosphates for Acros - being a Digitata (at least that's what the picture looks like) and not being the growth tips I'm less inclined to see low phosphates as the most likely cause.

I could for sure be wrong there, but the pattern of STN looks more like something's munching starting from the edges, not the tips?

Low phosphates/high alkalinity usually starts at the tips of branches of Acros - at least in my experience.
For sure burnt tips on acros and other up growing colonies. This looks like a plating type Monti or a hybrid, I could be wrong.
I would not rule out my hypothesis so early.

OP, have you actually seen evidence of pests? I'm sure you will look now!
I’m not sure the type of monti. It’s branching. I’m trying to keep nutrients up. I went from adding 5ml day of neophos to 25ml over the past couple months. Just to maintain. It can consume .05 in a day easily. It seems to consume 3.5 ppm nitrate a day. It’s 57 gallons of actual water. I have been looking for pests. I haven’t seen any. I ordered a magnifier, should be here Wednesday. The coral started out as a 1” frag is now branching outward about 4” and 3” upwards. All kinds of branches. What ever is going on is on the part with least flow from other branches blocking. I can see polyps moving in the area. I’m not sure on par. I haven’t afforded the meter yet. It’s about 16” deep from surface. 2 Kessil a360xe at 90% and t5’s right above. I haven’t changed light settings for 3 months.
 
Well that could be your issue. If the light is being blocked as well, it'll turn white.
 
I should say it can turn white.

My Birdsnest still has polyps on a lot of its base but the shaded part is almost completely white.
 
It’s getting good flow. Just not as much as other parts. The polyps are fluttering really good. It’s not shaded. I can see that the white is expanding towards the top of the base. Definitely has gotten bigger. There are shady spots on the other side from a branch. That area isn’t white. It’s just not as green. There are spots with less flow and they are fine. Gotta be something eating it I guess. I just don’t see anything except pods on it. I’ll be able to see better Wednesday when the magnifier arrives. It’s epoxied down, is there a predator I can add if its nudibranchs? I read a certain wrasse or a coral banded shrimp. Sounds like the shrimp would work at night. But idk if it would actually find that spot??
 

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