Red Growth on my Rainbow Fish

[OllieNZ]

I noticed this growth a while ago. It dosen't seem to be affecting the fish in any way, it is not getting bigger or smaller either. Any ideas what it may be?

 

[sanj]

Ollie,

it is hard to say. I think I only ever saw this in my own fish when i very first kept rainbowfish. Does it stay the same and are there any other marks or lesions on any of your rainbows? It is very easy for rainbowfish keepers to jump to the conclusion that is might be symptoms of myco infection, but if there is no wasting, lesions or lumps protruding through the scales I would just monitor it for the time being.

 

[OllieNZ]

Thanks Sanj,
No other marks on any of my other (10) fish. Although one had got very skinny (you could almost draw a straight line from lower jaw to tail) I put this down to stress due to moving house and having the fish in a temp tank during this time.
If it is myco will the symptoms show in other fish species as well?

 

[sanj]

Hi Ollie,

waisting away is a sign of myco, but again waisting can be a sign of other infections also. I dont think stress alone will cause waisting, but stress can comprimise the immune system. There is little point overley worrying about mycobacteria since it can come from many sources and seens entrenched in the aquarium trade anyway. The best you can do it maintain your system well and help to contain its presence. I guess you do regular water changes anyway.

Healthy fish can keep this bacteria at bay for a long time, but I personally euthenise fish that have open sores.

 

[OllieNZ]

Thanks Sanj
On balance I have euthenised both fish and will keep an eye on the rest. 25% weekly wc and they are now in their permanent home and shouldnt have to be moved again.

 

[dw1305]

Hi all,

There is little point overley worrying about mycobacteria since it can come from many sources and seens entrenched in the aquarium trade anyway.

I think Sanj is right and that it was Mycobacterium, my only venture into Rainbow fishes has been with Threadfin Rainbows, and I've always had 1 or 2 females die out of any batch I've bought, with very similar symptoms, in the first couple of months. After that the fish have been fine, haven't showed any further symptoms and have spawned etc.

cheers Darrel

 

[OllieNZ]

Darrel, have you seen any transfer between species as im hoping to add some A. Calvus and J. Transcriptus to my tank in the next couple of months and dont want to spend the money only to have to destroy all my stock in 6 months time

 

[sanj]

If you have myco in your aquarium and most of us will do, it can transfer to any fish, but different species seem to be affected differently. There does seem to be a link between mass inbred fish like fancy guppies, dwarf gouramis and rainbowfish like praecox. Esstentially poor geneticially inbred fish tend to have weaker immune systems and become susceptible to infection.

Mycobacterium can be found in tapwater, so it really is about managing your aquarium rather than trying to eradicate the bacteria.