Originally Posted by xxabc
Also, to iamntbatman, I believe pineconing is a symptom that heavily indicates dropsy, and is a very common symptom, however is not present in 100% cases of dropsy. Sometimes it's just heavy bloating, or who knows what else. We'll never know for sure, though.
Dropsy itself is actually just a symptom. Dropsy is a fluid buildup that results from kidney failure or malfunction, usually brought out by infection that spreads to the kidney. Because fish have a higher concentration of solids in their blood than in their surrounding water, they take on extra water from their watery environs via osmosis. Their kidneys process their blood and allow them to excrete extra water. When the kidneys fail, they can't do this so the water builds up in their bodies. So yes, the kidney failure happens before the fluids build up to observable amounts (resulting in the pineconing effect). By the time you observe the pineconing, the damage has already been done to the fish so even if the infection that resulted in kidney failure is treated and cured, the fish may suffer from dropsy for the rest of its life.
Off topic I realize, but I thought I'd address it. However, bloating from other sources (food issues, parasites, etc.) almost never results in the full-body swelling and pineconing you see with dropsy so that's why I brought it up in the first place.