The Goldfish is a tier 1 fish. Its quite weak but gets a speed boost when near other fish. It was once the only tier 1 fish in the game and the icon of it. Guardian still somehow kills sharks as it.
Stay in either the shallows or open ocean and eat floor orbs. It really not that hard to evolve from Goldfish anyway, just stay away from beavers and rays.
It can hide in anemone and ships to get away from predators, you should stay near these.