Pleco TB immunity?

[Kaijuaquatics]

Hi all!

So I was researching myco infections (more commonly known as fish TB) and came across a tidbit of information I've been unable to verify: the idea that catfish are immune to it.

Anyone have any sources on this? If so, is it only certain types of catfish or do things like plecos and corydoras also bear the same resistance. I'm very curious to see if it's actually true or not

 

[AquaBarb]

No sources to offer but from personal experience i believe more species do infact hold a better resistance to Tb.

I had a batch of dwarf neon rainbow fish about 2 or 3 years ago which had the dreaded tb infection. I did my best to treat them but we cant get the right meds here in the uk unless prescribed by a vet . I lost them one by one over a 9 month period but the 8 cories they were in the tank with had no ill effect from the infection and all of them are still alive and well to this day.

Most of the fish from Asia, South America and Europe have been around for a lot longer than some species like Rainbow fish. You probably talking 100,000+ years, and have been exposed to Mycobacteria since they have been around. Whereas rainbow fish (newer species) never evolved with Mycobacteria so dont show the same resistance.

 

[Colin_T]

Pretty much in line with @AquaBarb.

We discussed this issue a while back and people were finding Asian and South American fishes were much more tolerant of Mycobacteria species and didn't seem to get it as readily, or didn't suffer from it as badly as rainbowfish do. This was put down to the Asian and South American fishes having been around for a lot longer than the Australian and New guinea rainbowfishes that have only been around since the last ice age (10,000 years ago). The longer the fish have been around, the more chance they have to develop some sort of resistance to the bacteria.

There is no cure for Fish TB because the bacteria have a waxy coating over them and this stops medications getting through to the bacteria and killing it. In addition to this, the bacteria tend to develop inside organs and develop granulomas (clumps of bacteria) and this makes it even harder to kill.

 

[Kaijuaquatics]

No sources to offer but from personal experience i believe more species do infact hold a better resistance to Tb.

I had a batch of dwarf neon rainbow fish about 2 or 3 years ago which had the dreaded tb infection. I did my best to treat them but we cant get the right meds here in the uk unless prescribed by a vet . I lost them one by one over a 9 month period but the 8 cories they were in the tank with had no ill effect from the infection and all of them are still alive and well to this day.

Most of the fish from Asia, South America and Europe have been around for a lot longer than some species like Rainbow fish. You probably talking 100,000+ years, and have been exposed to Mycobacteria since they have been around. Whereas rainbow fish (newer species) never evolved with Mycobacteria so dont show the same resistance.

Yeah I've heard of rainbow fish being notorious for dying due to TB, it makes sense that resistance would be an evolutionary trait in older species. It would be a good study to conduct if anyone had the scientific knowhow or money haha. I might look for scientific journals later to see if there's any formal sources to back it up

I've heard some people propose bottom feeders don't generally get ill effects because they spend a lot of time sifting through waste and therefore don't develop the adverse symptoms consistent with other species. Whether that's true or not remains to be seen but the generally hardiness of most catfish species would be concurrent with that.

Myco is a very interesting topic to me because of how it operates. A recent article suggested that fish can be carriers with the mycobacterium remaining dormant (something which aligns with the resistance in older species). Its also been posited that a majority of dropsy cases in bettas are cause by myco which is what causes their immuno collapse. It would explain why unstressed fish die from it so easily, their immune systems aren't "on alert" so to speak which is why they spiral very quickly once they show symptoms. Although, I firmly believe overbreeding of bettas also contributes to their predisposition.

All of this is speculation on my part, but interesting nonetheless. Fish are illusive when it comes to diseases and it can be hard to both diagnose and understand how they operate. I wish aquatic vets were more widely available haha.

 

[Colin_T]

I think most Betta splendens that die from unusual symptoms are dying from health issues associated with inbreeding. They are so messed up now it isn't funny.

In addition to inbreeding, male Bettas are generally kept on their own for most of their life. This significantly reduces the chance they would pick up a Mycobacterium infection, unlike other fishes that are kept in community tanks where any fish in the tank could have or introduce the bacteria.

There is a chance they could pick it up from the food they get, with a lot of live fish foods from Asia being grown in less than sanitary conditions where things like Mycobacteria are common.

 

[Kaijuaquatics]

Bringing this back because I'm curious to see if anyone else has any information and/or input on this