Ok i have found out the cause of my problems. 2 of the Emporor Tetras have become agressivley territorial over the rock on the right hand sid. Im wondering wether its a male and a female that have layed eggs there or something, but all the other fish are staying on the left of the tank. If any go near them they are getting attacked, my gold guppy now has a tail tear aswell.
The emporors are going back today, its not fair just sending back 2 of them so all 5 will be replaced.