Gold fish is a soft type and it will not lovse without its company.Some other fish are cat fish,tiger fish,angel fish,salamon,kurrah and any other fish that is friendly in nature and adapt itself in the acquarium or the fish tank you have.But it is better to keep the gold fish away from aggrasives fish.
Goldfish should be kept together because they do not need an aquarium heater, their food is specialized to them, and they can harm the water chemistry needed by tropicals. Any variety is okay together, but fantails are slower and may be nipped. That said, you can often add Cory catfish of any variety.
You could try guppies and any sucker fish. Crabs are also compatible with goldfish. Catfish are also an excellent choice. Tetras are another option for sharing space with a goldfish.