Some loach species have been the toughest fish to net out of my tanks due to speed and agility. My 2 6inch yoyo loaches have been the most elusive for me to get out of the tanks. Even when I think I have them cornered, those darn things turn on a dime. If I don't drop the water significantly, I will wear my arms and shoulders out & never get close to them. Maybe not the fastest, but they're up there in our aquarium world