How to stop fish fighting with glass reflection?

[JasonVH]

Is there a way to reduce the reflection from inside the tank?

Female banggai has become obsessed with fighting/driving away the 'other female banggai' except it's her own reflection. It has gotten to the point she's starting to get a raw spot on her lip from pushing against the glass so often.

Help, please?

 

[JumboShrimp]

I have tried to drape a white towel over that pane of glass and lower the lights for a time; if that doesn't work I'll switch to a black towel. Sometimes it will 'break the habit' (along with changing up a few rocks as a distraction?), and after a day or two, the towel can be removed. Give it a try-- It can't hurt.

 

[JasonVH]

I have tried to drap a white towel over that pane of glass and lower the lights for a time; if that doesn't work I'll switch to a black towel. Sometimes it will 'break the habit' (along with changing up a few rocks as a distraction?), and after a day or two, the towel can be removed. Give it a try-- It can't hurt.

Thanks! Taped white paper on the glass a few mins ago to see if that works. She had a go a couple times, not sure if out of habit or she's still seeing herself.

The thing is, she primarily fights from the left and right sides(paper covering those right now) with the occasional go at the back and front. Sometimes she will be at one end and seemingly look over at the other end and then zoom over to have a fight.

 

[ISpeakForTheSeas]

The white paper is a good way to go, but basically the reflection happens because of a difference in brightness on the two sides of the glass - if you reduce difference or flip which side is brighter, the reflection on the side in the tank goes away:

glass shows reflections when there's a substantial difference in the amount of light on both sides (i.e. when one side is light and the other dark, the side with more light will start reflecting). So, if the lights are off outside of the tank but you have moonlighting or something on the inside of the tank, it's possible that the amount of light in the tank is enough to cause reflections on the glass.

For it being lighter in the tank and darker out of it, I've seen someone put a white piece of paper on the outside of the their tank to reduce the light difference inside vs. outside, and that successfully eliminated the reflection they were getting; some other suggestions include blocking the light from hitting the glass inside, or putting little LED's around the outside to light it out and decrease the difference in light.

As I mentioned in my initial post, these reflections appear when one side of the glass is brightly lit and the other side is much darker.

So, to get rid of the reflection, try lighting up the outside of the tank and see if that helps. One way you could do this is by running some LED strips around the outside of the tank so that they light up the glass. This thread might give you some more ideas too:
https://www.reef2reef.com/threads/moorish-idol-attacking-reflection.921566/