The tiger barbs will pester the goldfish and nip at their fins constantly. Some people will tell you that tiger barbs keep to themselves if kept in a group of 6 or more, but my experience is that anything with long fins is too irresistable for them to ignore... I tried putting mine with some long-finned rosy barbs and I had to take the rosies out of the tank before they got hurt! Tiger barbs work well with other more aggressive or fast fish with short fins. I have mine with some white clouds and a rainbow shark.
Goldfish prefer cooler water than most tropicals, although white clouds do well with cool water too...