Blue mark looks like bruising on my fish ?

Question

its two of my dwarf gouramis and its right on the bottom part of their head and a little part of the abdomen the other fish in the tank r fine wut is this and wut should i do

Answer 1

My friends have 1 dwarf gourami alone in its own tank and it has those marks and he is fine.  

Answer 2

Could have been due to a scuffle with your buddies, relax, and keep an eye out for more fights...if it worsens separate the aggressor.

Answer 3

they could of been fighting and was hit ect

it should heal