Also called a “minnow”, a “fish” is someone who keeps low amounts of cryptocurrencies. The fish or minnow is subject to the power of what is called the “Whale”, a crypto trader who has a “heavy wallet” or someone who has the power to impact the market with the mere sell of all his or her crypto tokens.
Given that the fish has a small number of cryptocurrencies, it does not mean that his or her supply will stay that way. The crypto trader’s crypto amount can and will grow eventually. And with the increase in his or her holdings, the fish will eventually evolve into a “Dolphin” (a token holder who owns a moderate amount of cryptos) and ultimately, a Whale.