Worm on Neon Tetra

[Greg H]

Has anyone ever seen this before or treated? Neon is acting totally normal but this been in like a bubble on him for a few weeks and has grown in size. 
 

[Guppysnail]

My eyes are not great so I can’t clearly see anything but a white line.  Here is some info maybe you can at least rule these out and perhaps your eyes are better than mine. https://edis.ifas.ufl.edu/publication/FA185

Grabbed some net pictures as well for you 

[jwcarlson]

Minor quibble, but that's a cardinal tetra, not a neon.

And it sounds like dermocystidium.

Quote

 

In Cardinals, Dermocystidium generally manifests as one or more bubble-like skin cysts reaching 5mm in diameter, each typically having a whitish worm-like structure inside. Hence it is easily confused as a skin-parasitic worm infection — and it’s certainly fooled me a couple of times!

So, if you see one or more protruding cysts on the body and/or fins of your Cardinals, each looking like a clear bubble, and some containing a white ‘worm-like’ tube inside, as you mention, then it most probably is Dermocystidium. Proof would be to burst a cyst (although I’m not suggesting you actually do this!) onto a microscope slide and look for thousands of tiny spores under high power of a microscope. These are the infective ‘zoospores’ that swim in the water in search of a new host.

 

From: How do I treat Dermocystidium - Practical Fishkeeping

[Colu]

I agree looks like Dermocystidium  from what I have read theirs no effective treatment

Edited January 30, 2022 by Colu