Swollen Goldfish

Question
I'm afraid to say that I'm not particularly an expert in keeping and caring for fish. I have a goldfish of an unknown variety, however it is fairly plain and was very cheap when my parents bought it for me. It has now been alive for over 8 years, which surprises me for a cheap pet. Problems only recently began occurring, whilst i have been away from home at university. When i was home for a brief visit the fish had looked slightly swollen, however no more so than when it had been overfed occasionally in the past, but upon returning home for my summer holiday the fish is extremely swollen, easily twice its normal size, and you can see blood vessels showing through the fish's skin. The scales are quite spread apart, though have remained flat to the fishes body, not standing out in any way. The tank is filtered and water changed fairly regularly, though I'm not entirely sure about this as I'm away from home more often than not. The fish has only been fed dry food whilst I've been absent. My family has only tried feeding my fish little/no food for periods to see if it had simply over eaten. I personally wonder if it is simply a bit too old now, but i would like to hear the thoughts of someone with more experience, as i would dearly like my fish to stay healthy and be around for as long as possible.
Apologies for the general vagueness, and thanks in advance,
Jeremy.

Answer
Hello Jeremy:  The oldest living goldfish on record was 43 years old and was a goldfish someone won at a carnival.  This proves that cheap and plainness are sometimes better then expensive and ornate.  If your fish is still eating I would... feed it some brineshrimp to see if he/she is constipated.  Is the fish pooping??? It is possible that if it is a female that she is full of roe/eggs.   It is also possible that she has a disease called dropsy... where they bloat up and eventually die... google dropsy and images ...and see if that is what she looks like.  It may also be that she has internal parasites or something along those lines.  If she is swimming around and acting normal then I would just feed her the brineshrimp... if she is lethargic and laying on the bottom... then I would medicate her... if she has dropsy she will need to be put to sleep as that disease is almost always fatal... please get back to me... dave