Is my yellow tang killing fish?

[skipo99]

Tank set up 300l

inhabitants
Yellow tang
2xclownfish
Black Lep wrasse
Then I had a peacock wrasse and a dart fish.

parameters
1.025 salinity
8.6kh
1350mg
440 cal
Nitrate 5-10
Phos 0.03-0.1

everything been in the tank for approx 3 months, tank is 7 months old.

all fish where getting on fine and eating well. 2 weeks ago my peacock wrasse was on the sand when I got home at first thought the inevitable had occurred but when I went to get it out it shot off into the sand to sleep. Next day still was acting the same and my tang grabbed its tail abit so put it into my QT tank to see if it would recover. Dart fish was hiding more than normal but did feed. Last night my dart fish was out still moving but resting more on the sand. Noticed a cut or mark on its stomach as shown in photos. Removed him to QT and he died after a couple hours.

im unsure if this damage is from the tang and he’s killing fish or if it could be down to something else. I do have an emerald crab also. The ripped tail on this dart fish was from months back when I had an aggro wrasse who I returned due to its bullying it had healed since.

 

[DrZoidburg]

Anyone else blame the crab? I personally lost 6 anthias to a crab. On the other hand have lost fish to a tang as well. I lean towards it maybe being the tang cause if it was a crab it would pull fish into rocks, and you might never see it again. It could be either of them.

 

[skipo99]

Anyone else blame the crab? I personally lost 6 anthias to a crab. On the other hand have lost fish to a tang as well. I lean towards it maybe being the tang cause if it was a crab it would pull fish into rocks, and you might never see it again. It could be either of them.

The crab is on the large size for an emerald. But it’s been in there a long time with the firefish approx 3 years. I also thought the same if the crab got it while it was sleeping it would have never been seen again, also I think it happened in the day as it didn’t live long after I got home.

 

[DrZoidburg]

If it wasn't for the other fish acting strange. I would say it is possible old age. What strikes me thinking back on a similar instance I had with a tang. The yellow was dragging a convict tang equal size around the tank by almost the exact spot as on your fish.

 

[skipo99]

Could that kind of damage happen with old age? It did have some lumps pop up occasionally on its abdomen over the last 6 months which I thought was likely due to age.
Seems a big coincidence two at the same time. Wrasse has no visible damage and only saw it grab it’s tail when it was already Sick. Wrasse is still alive after 2+ weeks but no improvement

 

[DrZoidburg]

Well if fish died, and sat there for some time before you noticed it could of rotted out in that spot. May be not of been a bite mark at all. Possibly picked on after death. It also could very well be from damage from another fish. Hard to say if you didn't actually see it.

 

[RichardR]

agree - a difficult assessment especially if the fish have been together for a long period of time.

 

[Reef AquaCult]

Not the YT

 

[4FordFamily]

That doesn't look like damage from a YT or tang. Of course, it could have bullied the fish to death but tangs normally ignore fish that don't compete for a food source or are not similarly shaped. I'd be shocked if this was the work of a YT or any tang. Though any fish can eat the stomach out of a deceased fish.

 

[Garf]

If the tang had done it, I would expect it to be sliced to the bone.