Thanks for your reply
The gourami is still small, I also have some young angels which I guess could also be the culprits but they have shown no signs of aggression towards any of the other fish.
The tank is 200L, 1000mm long
I have in it:
BN
khuli loaches
cories
Betta (1 male)
angel fish (2 young)
balloon mollies
SAE (he is a possible suspect too)
harlequin rasbora
leopard danios
neons
assorted guppies, mostly young
platies X 2
I have also since noticed that 1 of the leopard danios has been attacked, she has blood near where her front fins and anal fin join her body.
I plan on putting the Betta in a breeding trap tonight and see if there is any more damage over night.
Who ever the culprit turn out to be will not be sticking around.
I am quite upset about my danio as they were the very first fish I got when I set up my first tank and they have grown gorgeous long fins and I am very attached to them
I don't think any one apart form the guppies and the balloon mollies are interested in breeding and I have never seen any aggression from them