1: is an early ucler 2: looks like the scale underneath (the missing one) just nicked the skin when it came off, however it might get infected and cause an ulcer 3 and 4: not sure what im looking at, other than the slighty pink bellies, which is just caused by the stress of the winter. Is that what you meant?
In terms of treating the ucler, unforuntly its still a little too cold to use treatments (as the effectiveness drops in colder water). You can however add pond salt to the pond which should calm down the ones which are a little stressed and should stop the nick and the ulcer developing too much more before it starts to warm up
One thing i did see is an angling fishing net, do u go fishing? If so do u use seperate nets?
Did not answer your question about the fishing net. No, I am not into fishing, use to be in my younger days. My Dad gave me the landing net. He is really into fishing and would love to hook the Carp that is my pond. The Big net comes in handy for catching the fish and clearing the Blaanket weed...
It looks like a cross between a common carp and a ghost carp, and the long one looks like a cross between a mirror carp and a ghost carp. Chagoi's are usually to be much lighter colours and are just one colour.
In terms of a treatment, depens what is sold in your area, the first one id recommond would be knockey koi's treatment (forgot the name), then the NT LABS treatments aare good and after that then the interpet anti-ulcer is a good one.