I just got a mimic lemonpeel tang and my normally shy, peaceful kole tang immediately started bullying it.
Is this typical for kole tangs? Is there anything I can do? I’ve read that taping a mirror to the outside of the tank may help.
Will this behavior go away or will i need to rehome one of the 2?
Update: The aggression seems to have tempered off a bit. The kole tang is sticking to the rockwork and the mimic tang is staying higher in the water column.
Fish are all aggressive towards similar species especially tangs.
Little trick is to pull the dominant fish out for a couple days rearrange the rocks a little and when you put it back in it should be betterlol, anyone want to buy a kole tang?
Just kidding. I reallllly wanted to avoid rearranging the rock because there are so many corals attached to them.
I don’t have another home for the kole to move it to for the time being. If it gets to be a huge problem I will have to rehome one of them.
Generally speaking every tank has a dominant fish - when introducing a new fish the dominant fish will feel it necessary to flex it’s gills and display it’s dominance to the newcomer. It usually subsides anywhere from within a few hours to a coupe of days.
Like Bill said - rearranging the rock work while the dominant fish is out of the tank is an almost sure fire way to introduce new fish, but it can be a little annoying to downright pain in the butt to do. Another idea (although too late this time) is to introduce the new fish at night after the lights have been out a while and the existing fish has gone to sleep for the night, when it wakes up in the morning it doesn’t realize a new fish is in the tank.
You might want to try just turning the lights off early and leave them off a little longer than usual tomorrow.
You can also feed the tank - nori specifically - the kole will focus on eating and forget to chase the mimic, and once it sees the mimic isn’t competing for food (because 90% of the time a new fish won’t eat right away) it will determine it’s not a threat to food or habitat and let it alone.
good advice from everyone. I turned off the lights and it’s night and day (pun intended). They are best friends all of a sudden…
I saw DPA had a bunch of Mimic’s in a few weeks ago…I think they’re all gone now. I didn’t know much about them at the time. Theirs were all juveniles, and I didn’t realize how awesome they look as adults. Hope everything works out with them getting along man, as I’d kinda like to get one of each myself now. They are fairly similar in body shape, so I can understand their aggressiveness since they weren’t both added at the same time. I hear thats fairly common about similarly shaped tangs.
Just wanted to update you all since you gave me advice super quickly…
They do not fight very often anymore. Once in awhile the kole will nip at the mimic during feeding, but otherwise they get along well.
I actually like it better now with teh mimic, because the kole tang actual swims around the whole reef instead of just his little hiding spot.
These guys do a number on algae!
Good to see that the chasing and beating stopped 
By the way good thing you got him young, IMO this fish struggles to settle into the aquarium life once you get him as an adult from the shop… can’t wait to see how he changes! GolfC