what a very sad situation you have there,
you have the wrong combination of fish for a start.
Goldfish need a tank as said brfore of at least 55glns
that gold fish had
the capability of growing to 14-16 inches.
it is suffering from sceptisemia(sp) and the out look is poor,if not fatal. :(
they make a lot of mess,so a 10glln is not suitable for Goldfish.
the other fish are tropical,and need to be in a heated tank.the tank needs a filter,and the tank would need to be cycled.
here is a link to give you the information you need. http://www.fishforum.com/viewtopic.php?t=343
water changes are more important than you realise(don't mean to sound rude there).
you can turn this situation around and have a better time of fish keeping,
just need to follow a few guidelines.