Thanks everyone for all your words of wisdom. Sounds like I have a serious problem because I haven't been able to find anything on the net which claims to be a cure for hikui (ie consistent permanent fix), or even found a definition of what it is. eg if it is a virus (?) does it lie dormant in fish without hi and then can spread to fish with hi? Does this mean I have to get rid of all my fish, including the ones without hi and start again? I now have it breaking out or present in 4 out of 10 fish in my "display" pond. Pretty depressing stuff.
