Naso tangs suddenly aggressive.

[bevo5]

So.....I have a 200g, fairly lightly stocked tank. I've had two medium blonde naso tangs (6in tops) for about 8 months now. I got them as a pair, but they were a bit small so I wouldn't be surprised to learn I got two males. Either way - they always swim together, hang out together. Seem like buddies.

Well, I recently did a 72hr blackout to try and kick a minor dino issue before it blew up. That wrapped up thursday night and I put my moonlights on like 5%.

I went down shortly after and for some reason the smaller (what I thought was female) naso was chasing the larger male - who has smallish streamers for whatever that's worth as far as sexing.

Woke up Friday and the male is pinned in a corner just beaten to hell. He tries to get food and is straight up attacked. Biting, tail swiping, bullying etc. SO I put him in my sump - and he's doing better.

Question - is putting him back in a lost cause? Should I even try? I could do an acclimation box or the mirror trick.

Just odd that they were together for months. I guess the lights went out and they forgot about each other or something. Then the lights come back on and it's war.

Thoughts? I loved having the two together.

 

[Brew12]

So.....I have a 200g, fairly lightly stocked tank. I've had two medium blonde naso tangs (6in tops) for about 8 months now. I got them as a pair, but they were a bit small so I wouldn't be surprised to learn I got two males. Either way - they always swim together, hang out together. Seem like buddies.

Well, I recently did a 72hr blackout to try and kick a minor dino issue before it blew up. That wrapped up thursday night and I put my moonlights on like 5%.

I went down shortly after and for some reason the smaller (what I thought was female) naso was chasing the larger male - who has smallish streamers for whatever that's worth as far as sexing.

Woke up Friday and the male is pinned in a corner just beaten to hell. He tries to get food and is straight up attacked. Biting, tail swiping, bullying etc. SO I put him in my sump - and he's doing better.

Question - is putting him back in a lost cause? Should I even try? I could do an acclimation box or the mirror trick.

Just odd that they were together for months. I guess the lights went out and they forgot about each other or something. Then the lights come back on and it's war.

Thoughts? I loved having the two together.

@4FordFamily would be a great one to help with this.

 

[4FordFamily]

Unfortunately in a tank with not a lot of tangs or fish but with two naso tangs you were at a high risk of this happening eventually.

Mixing naso works better if not the exact same species and if one is clearly larger and male and one clearly female. It also works best with many other tangs present. It's always a risk when mixing any tang. Sounds like you have a rare aggressive naso, unfortunately your options are to remove the aggressor or the defender. I tend to remove the aggressor although a case can be made either way depending on your future plans.

I wouldn't bank on being able to bring those two back together, unfortunately.

 

[bevo5]

Got it and makes sense.

There are 15 total fish in there but only other tangs are a smallish yellow and a 6in white tail. Otherwise it's your typical mix of reef fish...wrasses, clown fish, hawks, etc. SO maybe not a lot of targets.

It's weird because the aggressor is the smaller one that was sold as the female. The larger one is a good inch or so bigger but is the defender...although mostly just a punching bag!

It's impossible for me to get the aggressor out without tearing things down, and I alreayd have the defender out so I may just nurse him back up to health and move on.

Thanks for the advice.