Originally Posted by
hheath541
did you completely clean and/or treat the tank after the other fish died? it might have been the fin rot that killed your fantail. it's been known to effect the gills. it could have also been a bacterial or fungal infection from having dead fish in the tank.
it's best to clean a tank after an infection kills off fish. you can also buy tablets to drop into the tank that kill off the infection, and turn the water green for a couple weeks.
on a side note, the people who work in the walmart pet department know nothing of where their fish come from or their ages. most of them know very little about fish at all.
it may have just been a small fantail to begin with. fantails come in 3 sizes; small, medium, and large. most fish reach full size in the first few weeks of their lives.
if you plan on getting any more fish i would suggest a full cleaning of the tank first, and the installation of a filter system. drain out all the water. wash any gravel or rocks you have at the bottom. wash the tank itself.
also, if you plan on getting more goldfish, you'll need to prep the tank. goldfish needs certain chemicals in their water to thrive. chemicals that their own bodies produce. it's best to get a few feeders to prep the tank. just let them live in the tank for about a month before getting the fancier, and more expensive, goldfish.