Firefish nipped fins

[SurfTrack]

Ive been noticing that my two firefish are always having nipped fins. Why is this? Should I worry? There are tons of hiding places in the tank. My only guess is that the orange spotted gobies want to hide in the same holes and they fight.

My other fish are
- Yellow tang
- 2 Clownfish
- 2 Orange Spotted Gobies

 

[Gareth elliott]

How long has the tank been setup? Were the firefish purchased as a true pair?

 

[SurfTrack]

How long has the tank been setup? Were the firefish purchased as a true pair?

Tank has been setup for about 2 years. I purchased the firefish on live aquaria about 3 months ago, they were not a true pair.