Autopsy for small fish

[LyraGuppi]

Does anyone have any advice on how to perform an autopsy on a betta? Plumley has had some form of fluid buildup for about a month, internally, which didn't react to any medication. He finally slowed down to the point where I think he'll die in the next day or so. I'm going to try to euthanize him so I can perform an autopsy on him, but how do I do it with him being so small? I have tools and I'm not squeamish.

EDIT: I did find a rather professional guide on fish autopsy, I suppose I could wing it for his small size. When I do, I'll take notes and photographs.

 

[LyraGuppi]

Since he was so small and (sorry) squishy, I couldn't perform a good autopsy. I pulled quite a bit of yellowish gel-like fluid from the perinoteal cavity. The best diagnosis I could come up with, only based on the human body's functions since fish anatomy isn't as well-researched, was cirrhosis of the liver. (Ascites) I'm still not 100% sure, though, that's just my sort of educated guess.
It was hard to have to manhandle him, and take knives to him, and not do able to respectfully put him to rest, and still not know exactly what went wrong. I wouldn't do this with a very small fish unless I really need to.

Notes in case anyone is interested:

Body Appearance pre-euthanasia:

• pale, clamped fins
• bloated, slight pineconing
• slightly bent spine above site of fluid
• showed fluid externally, you could see light through his belly

Body Appearance post-euthanasia:

• stomach can easily be depressed with a light touch

Internal Appearance:

• large amount of yellowish fluid pulled from perinoteal cavity, turned into gel-like consistency when out of body

Fluid does not show under microscope

Age: 2 yr, 6 mo
Species: betta splendens
Death: put under with clove oil, severed spine pre-autopsy
Disposal: Body flushed, guts burned

 

[LyraGuppi]

final picture before autopsy

 

[FroFro]

This is depressing.

 

[LyraGuppi]

Sorry. I thought it'd be best to leave my notes in here just in case something like this happens again, or I need to try another autopsy.

 

[Essjay]

I find this interesting.
Several years ago I had a peach coloured plakat who showed the symptoms you describe, except that he also had a large bulge on one side of his abdomen. Once it became obvious he was suffering I put him down. When I investigated, I also discovered his abdomen was full of a yellow goo.
I never did find out what it was but it sounds very similar to your betta.

 

[LyraGuppi]

Interesting! I was wondering if it was a tumor, but ruled it out since the bulge was symmetrical.