It pains me to do it

Jesterrace · Jun 27, 2018

but I may have to get rid of my Yellow Tang. Noticed about a week ago my Coral Beauty Dwarf Angel had a small chunk missing out of it's lower fin (which coincidentally was about the exact same size as the Tang's mouth). It has been healing over the last week and is pretty close to being almost as good as new, but today I observed the Yellow Tang back up towards it and give it a tail whack (which isn't good given the scalpel on the tail) and has been flaring it's fins around it. The Coral Beauty appears to be okay but there was a little bit of surface damage to it's left side. This is incredibly frustrating as I have had these two together for over a month and the Yellow Tang and Coral Beauty were added together and even shared the same holding tank at the LFS for several weeks with no problems. The Yellow Tang has also been bugging my Wrasse to a lesser extent, but no damage that I can see. I know that Yellow Tangs can be jerks, but it is frustrating to see things going so well and then all of a sudden the Yellow Tang developed an attitude for whatever reason. I do keep the tank well fed (ie 2 small feedings of reef frenzy per day) and 1-2 feedings of seaweed per day.

It's a 90 gallon tank with the following stock:

Yellow Tang
Coral Beauty Dwarf Angel
Pajama Cardinalfish
juvie Melanurus Wrasse
Cleaner Shrimp
Handful of Hermit Crabs (red legged and left handed)
A bunch of snails

1WildBill · Jun 27, 2018

Can you put the tang in an acclimation box for a week and set it inside the tank?

Eastlake · Jun 27, 2018

It's possible that the tang's territorial nature has out grown the size tank that you have. My sister had the same issue with a sailfin tang. It was tiny when she bought it and it was peaceful for years, once it grew to a certain size it demanded every square inch of the 90 gallon it was in and it wasn't until we moved it to my 150 gallon that it finally calmed down and stopped killing other fish. You could try an acclimation box and perhaps re-arranging the aquascape to see if that will calm it down and allow the other fish to re-establish themselves but my initial thoughts are that the tang just needs more space.

Jesterrace · Jun 27, 2018

Eastlake said:
It's possible that the tang's territorial nature has out grown the size tank that you have. My sister had the same issue with a sailfin tang. It was tiny when she bought it and it was peaceful for years, once it grew to a certain size it demanded every square inch of the 90 gallon it was in and it wasn't until we moved it to my 150 gallon that it finally calmed down and stopped killing other fish. You could try an acclimation box and perhaps re-arranging the aquascape to see if that will calm it down and allow the other fish to re-establish themselves but my initial thoughts are that the tang just needs more space.

The Tang is still relatively small (about 4-5 inches in length) and given that the tank is very lightly stocked (only 3 other fish) I figured it should be okay. I had him in an acclimation box for several days when I added him, so I am not sure how much the time out will work and the re-arrangement of the rockscape is out of the question as it took us some time just to get everything locked in and stable. I agree it could be that it has simply marked out it's space as the tank. I will attempt to trap and remove it.