i could be wrong... but gobies get big and they usually need cold water... so that could be part of your problem.

so many people think... i'll start with guppies, or goldfish... something easy. these are NOT easy fish. they are soooooo inbred that they die off really easy. we called the livebearer section in the store the "tanks of death" when i worked at my local fish store (lfs) and goldfish are the number one poopers of the fish world and need a minimum of 10 gallons per fish!!! so when someone puts a few of them in a ten gallon tank... and wonder why they die... well,... DUH!

if you want to get a little tank going and not have them dieing... get a group of danios. they are soooooooooooooooooo hardy! of course that means i get to pplay with your ferrets!

or you could invite me over and i can set up a tank for you! heehee