Some domineering online names for fish include: A Mix of Fish and Dragons, Shark Overlord, etc.
1. A mixture of fish and dragon: This name combines "fish" and "dragon" to express an aura that is both ordinary and powerful, implying both ordinary and extraordinary, and a mixture of different elements and styles.
2. Shark Overlord: This name combines "fish" and "shark" to express a domineering and ruler temperament, implying hegemony and dominance in the ocean.