HITH is not transferred between fish.
Also here is a study conducted for HITH and the link of carbon.
With thanks to my colleague (Ari) who’s a member of the WAVMA, he’s shared this new finding. For a long time, HLLE has been a difficult to diagnose condition because of the multifactori…
thefishvet.com
Yup I've seen that but it's anecdotal at best. It doesn't go into enough of the other possibilities like, water quality, nutrition, and others. There are better arguments for and against. I'm just saying it's never been proven either way.
I ran carbon with surgeon fish and the hlle they had before coming into my care healed. So what does that say? I also carbon dosed to remove nitrate. I know it's not quite the same but it's added carbon.
It's still very unclear as to the causes or should I say additional factors.
Ive never heard of it being contagious or not. It was just a theory as to why none of them had it until this one with it was added.