Fish nipping cause RTN?

[Dorado]

I have a tenuis that has been doing great, nice growth and polyp extension. Then about a week ago I noticed its polyps were somewhat retracted. I didn't really think anything of it until the poor polyp extension continued for a few days and I decided to perform a full test on my water parameters. Everything looks great and has been consistent. After observing my tank for a while, I noticed that one of my springeri damsels is nipping at the tenuis' polyps, but luckily it only seems to be interested in this colony. The next day the tenuis started RTNing midway up one of the branches. I immediately put in my fish trap but haven't been successful as of yet. As the flesh began quickly receding, I clipped off the affected/infected half of the colony, trying to frag what I could. Has anyone else ever dealt with this before? fish nipping causing RTN? Or is it more likely something else that infected the stressed/nipped coral? Here is a shot of the colony maybe a month or two ago.

 

[Dburr1014]

I have a tenuis that has been doing great, nice growth and polyp extension. Then about a week ago I noticed its polyps were somewhat retracted. I didn't really think anything of it until the poor polyp extension continued for a few days and I decided to perform a full test on my water parameters. Everything looks great and has been consistent. After observing my tank for a while, I noticed that one of my springeri damsels is nipping at the tenuis' polyps, but luckily it only seems to be interested in this colony. The next day the tenuis started RTNing midway up one of the branches. I immediately put in my fish trap but haven't been successful as of yet. As the flesh began quickly receding, I clipped off the affected/infected half of the colony, trying to frag what I could. Has anyone else ever dealt with this before? fish nipping causing RTN? Or is it more likely something else that infected the stressed/nipped coral? Here is a shot of the colony maybe a month or two ago.

I don't think it's the fish, imo.
Recent pics?
Post parameters. Anything else change in the past couple months?

 

[Maoiwowie]

I dont believe so either. My angels regularly lunch on my sps if i forget to feed them.

 

[jda]

I have had some completely irritating polyp picking fish. They corals never seemed to suffer too much and never had any STN.

Pests, elevated building blocks and point-source lighting as colonies grow as my main three things to look for.

 

[Dorado]

I don't think it's the fish, imo.
Recent pics?
Post parameters. Anything else change in the past couple months?

Yeah, I didn't really think so either.

No pics, I already hacked up the colony to try and save a frag or two

Parameters:
temp- 78-80
salinity- 1.026
Nitrate-25
Phosphate- .1
Alk- 8.5
ph- 8.2-8.4
Cal- 470
Mag- 1350

Coincidentally, I had sent out an ICP a couple of weeks ago because I moonshine and just received the results. The only thing that is a little concerning are that my silicon levels are at 450ug/l, but my tank has been at these levels for several months with no ill effects. All other SPS and clams look great and have nice polyp extension.

The only thing a little out of the ordinary is that last week I added the surfzone sand activator from IPSF to keep up my bacteria levels.

 

[Dorado]

I have had some completely irritating polyp picking fish. They corals never seemed to suffer too much and never had any STN.

Pests, elevated building blocks and point-source lighting as colonies grow as my main three things to look for.

I don't appear to have any pests, I've been watching like a hawk but may dose some interceptor just in case.

What exactly do you mean by building blocks?

I don't have point source lighting, I run T5s and LED bars, but this colony is located right in the middle of the tank about 6" below the water line

 

[Dburr1014]

I don't appear to have any pests, I've been watching like a hawk but may dose some interceptor just in case.

What exactly do you mean by building blocks?

I don't have point source lighting, I run T5s and LED bars, but this colony is located right in the middle of the tank about 6" below the water line

Hmmm, numbers are great and by the sounds, stable.
Check at night with a red flashlight.
Keep us posted.

 

[jda]

no3 and po4 are building blocks of life - a nutrient, but not energy like most people think of nutrients. Too high can be an issue for some acropora while others have no issues at all... some will stn and some just continue growing. If you want to keep anything, anywhere at any time, po4 and no3 cannot be too high. This can be while some die and some are OK for hobbyists. Nitrate of 25 can cause some issues for acropora - I have a handful that would not be happy at that level and others that would not even notice.

If you have T5s and light surrounding your coral, then it is not likely a point source light thing.

Nobody ever thinks that they have pests at first. I hope that you do not. Check very carefully.

 

[LOVEROCK]

Check with a held held jewelers piece , most of the pest is invisible to our naked eyes

 

[ScottB]

but this colony is located right in the middle of the tank

As stated before, your numbers are fine. Spring damsels are good aefw predators so I keep them but never had a problem with them picking on acro. My coral beauty on the other hand... but still no tissue necrosis just limited PE.

So I caught this little nugget in your post and speculate it is most likely the problem. FLOW gets crushed as your other colonies start blocking it in the center of the tank. Happens to me every time without fail. Every 3-4 years I rip out and start over.