OK now this is really WEIRD. My fish formed a bubble and NOT a good one...

[xXInkedPhoenixX]

This may be related to my bolivian ram thread here BECAUSE it is in the same tank but I've been having issues with the Black Neon Tetras in my Angry Man tank for a while. ONLY the females will bloat and bloat and bloat like Violet Beauregarde and then die. I've tried QT, meds, soak and slowly my numbers have dwindled. NOW there's a new one. Yes she's still bloated and I've isolated (but yesterday she was not like this) and now she has a clear bubble out of her own bloated bubble body! W T H?! @Odd Duck @Colu ever seen this before? I'm half tempted to pop it but I doubt that is the right course of action.... This fish, I don't think is saveable but I think I might need to bomb the tank maybe not only with Maracyn2 as is the plan because of a popeye infection in my bolivian but also for whatever is going on here? EVERYONE else in the tank is uneffected- all 10 of my Harlequin Rasboras are perfect, my new SAE, fine, other Black Neons also ok but for one other female now bloating up but NOWHERE near as bad. Whatcha all think?  

[Colu]

Looking at how bloated the fish is I don't think it will recover even with treatment it could be polycystic kidney disease that can cause large fluid filled cyst  the fact it's only affecting the black neon tetra it could be a pathogen  that your other fish have developed immunity to it if the black neons Tetra were the last fish your added to this tank that could be why it's only effected them @xXInkedPhoenixX

Edited February 4 by Colu

[Odd Duck]

Definitely very strange but appears very unlikely to be something the fish will recover from.  Not sure what could cause that but an intestinal infection and sepsis (infection in the blood / entire animal) seems most likely. Probably with a gas producing species of bacteria to cause that bubble.  I would recommend euthanasia then would do a post-mortem exam.  I might try inserting an extremely fine gauge needle like using an insulin syringe and aspirating / draining that clear bubble to determine if it’s gas or liquid.  Then open the fish and look inside.  I don’t know what the nearest university would charge for a post-mortem exam but that’s your best chance at figuring out what’s causing the issue.  Sorry I’m not more help.  With only females affected I would first think a reproductive issue like egg-binding, but that shouldn’t cause a bubble like this.  I have nothing brilliant for you.

[xXInkedPhoenixX]

 Unfortunately little one passed and I have already disposed of the body. My assumption is the damage with that extra bubble was by me accidentally putting a little pressure on an already overinflated fish when hand catching out of the tank. The bubble was still mostly inflated when I pulled them out of the water, but slightly deflated when I took them out and they sat for a minute while I prepped to dispose of them. @Colu @Odd Duck just fyi