I have 2 giant fish, their about 5 inches in length and 8 inches around the one is a black moor and the other one is a ryukin and I have a 300L tank and I have 2 pond plants in their and loads of stones I bought the tank second hand from a fish store and was apparantly cleaned properly and looked brand new the guy gave me stones that were apparantly good for the fish and easy to clean which I didn’t like the colour but what evers best for my fish I’ve had them all set up for a month and I’ve had to clean them for the first time and I’ve noticed little bug things like seamonkeys and triops are stuck on my fish and seem to be going under their skin? I don’t really know? I’m taking them to the vets soon when I have the money but can anyone tell me what this could be?
Thanks 
I’m really concerned as they were £85 for the two and I absoloutley love them too bits! <3