Contradicting information on cotton mouth/ columnaris?

I have a neon tetra with a small white bump on the side of its mouth. Many sources I've read on columnaris, including the one here on fishlore, suggests that columnaris is always present in the water but only proliferate when a fish is stressed or hurt. However it also says that it is highly contagious. Can someone explain to me how it can be highly infectious if no other fish is stressed or hurt?

Is it ok to leave this one neon tetra in with the others and watch him for a few days to see if it is indeed columnaris. Or will the risks be too high? I've had a lamp eye tetra in my first tank with the same symptoms before except a bit worse. I didn't know better at the time so I just left him in there. The problem has since corrected itself and nothing happened.

Thanks!

 

Bumps on the neon tetras are seen more and more.

Cause those don't seem to be contagious, neonspecific, not treatable, etc.... to me.it can't and won't be Columnaris (more fluffy) but probably a viral issue like Lymphocystis.

All the threads have proven you can leave the fish, can treat infections if they occure but not the bumps. The others might catch it but not sure it they will.

 

Thanks for the reassurance, I'll just keep an eye on it over the coming days. It also has a bit of fin rot. It came with the fin rot when I purchased him about 1 month ago and hasn't gotten any worse.

I see you're a 'fishlore legend' haha. With your experience, do you think columnaris is as infectious as most sources say they are. I still don't understand how it can be so infectious if it only infects stressed fish. All the fish in my fish tank shouldn't have any stress; it's understocked, good filtration, and I do weekly water changes. Really hope it's not columnaris.

 

There are different strains of Columnaris and there definitely is one in bred neons nowadays. That one isn't contagious for other species and its infection depends on the circumstances the fish are kept in.

Finrot is one of the signs of this strain (and some believe the bumps are as well).

So if you've a stressfree environment and keep your fish in clean water / understocked that should improve this.
Keep a close eye on them and some meds by hand in case of worsening / infection.

I will call in Steve Redshark1 to give his experiences and maybe more clear info on this issue.

 

There are different strains of Columnaris and there definitely is one in bred neons nowadays. That one isn't contagious for other species and its infection depends on the circumstances the fish are kept in.

Finrot is one of the signs of this strain (and some believe the bumps are as well).

So if you've a stressfree environment and keep your fish in clean water / understocked that should improve this.
Keep a close eye on them and some meds by hand in case of worsening / infection.

I will call in Steve Redshark1 to give his experiences and maybe more clear info on this issue.

Thanks so much!

I've noticed a lot of unhealthy looking neon tetras in the shops too compared to other fish.