Goldfish has small lump on tail

Sooz

New Fish
Jan 28, 2010
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#1
Hi
We have a goldfish about 7/8 yrs old in a 125 litre tank - 1/4 tank changed every two weeks - fed on flakes & Tetra fresh treats twice a week. A small lump has appeared on the very edge of his tail which looks slightly pinkish compared to tail colour - it is not fuzzy at all and the rest of his tail is fine - it doesnt appear to affect him and he is acting and eating the same as usual. I've searched thro pics and forums and cannot find anything like it - I would be very pleased if someone could throw any light on what it may be - I enclose pic.
Many thanks
Sooz
 

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