When male rainbows spar, do they cause damage?

[Spiskits]

Rubbing?

Nope. They act perfectly normally. I watch them a lot as the tank is in my dining room so every mealtime is spent observing the fish. They act no differently to any other fish in the tank. In fact, now I've closed my blinds (it's actually sunny today!!!) all the rainbows are flashing and chasing around. The Boesemani's are well in there as usual.

 

[Spiskits]

It's not Columnaris.

It doesn't look like TB ulcers either.

It just looks like a few scales that have been damaged.
Add 1-2 heaped tablespoons of rock salt per 20 litres to the tank and keep it in there for 2 weeks.

OK Thanks, Colin_T I'll give that a go.

 

[Stan510]

They might nip each others fins is the worst I've seen. But no bullying to death like other fish species seem to do. They are easy going..just show off to each other is about it.