Stressed Fish Behavior

[bcarl77]

Not sure how to explain this, but I have noticed some very odd behavior from my Yellow Tang over the past week. He has been in the tank (130gal) for about 3 months, he is always cruising around patrolling and doing normal tang things, picking at nori, rocks, etc. Recently he has been hiding behind a rock in the back, picks at the rocks occasionally, hides, occasionally comes out, and is eating very little (usually an aggressive eater during feedings). I have been inspecting him daily and see no signs of disease, discoloration, heavy breathing, fin rot/damage, etc.

The only changes I have made to the tank is shortening the light cycle from 12 hrs to 7 and adding 20ML of Microbacter7 (5ml/20gal) daily to help combat cyano. All other water parameters look great and all other fish are active and eating normally. Could any of these things cause fish stress?

 

[bcarl77]

Anyone? @Humblefish?

 

[kireek]

He sure sounds like he is stressed or sick.I don't know what would be causing it though.Possibly the new light schedule as you suggested.

 

[bcarl77]

I put a camera on the tank while we were away. He did come out and eat a small amount of Nori but not swimming around like himself or come out to eat frozen

 

[Eva Rose]

What other fish are in tank?

 

[Greg P]

Do you run a skimmer? I do and noticed a slight drop in my pH while using MB7
This leads me to believe a drop in O2.
The other thought is the lowered lighting schedule may also be adding to lower O2 levels due to your algae producing less from lack of light.
Just a couple thoughts, but nothing concrete ...

Do you have kids or pets who could be scaring him/it?

 

[bcarl77]

I stopped dosing MB7 the last two days and the fish are appearing to be more active each day. No changes around the house that may be scaring him. It's hard to gauge the O2 theory. I am in Florida and it has been quite hot the past 3-5 days so the A/C has been running which also drops my pH a bit. Per my Apex average pH is down roughly .05.

 

[Eva Rose]

What other fish are in tank?

Often when a fish hides, barely out, not eating it can be other fish intimidating it. Fish can get along for a long time, then when another tankmate matures, that fish might start to exert dominance over fish it ignored before.

Of course it could be other factors illness, etc. But you might try an extra nori clip near his current hiding place. See if it entices him to come out more.