Piranha

Piranha are viruses from Mega Man Battle Network and Mega Man Battle Network 6 games. These viruses have a fish-like design. When in battle, Piranhas move up and down the column in which they are located. Their arms are constantly rotating in a propeller-like fashion. When they first move to a panel, they release a lock-on crosshair traveling forward into the players direction. If there are no obstacles in the way of the traveling crosshair, then the virus moves onto the next panel and repeats the attacking process. If the crosshair lands on the player, it will quickly attempt to lock-on, resulting in the virus shooting out metallic arrow from within its mouth, traveling forward (the player is still able to move away even if they are locked onto, to successfully avoid the attack).

Piranha
Piranha have green-colored scales and orange-colored fins. Their arms and face is of greyish tone.

Piranha2
Piranha2  have red-colored scales and yellow-colored fins. Their arms and face is of pale-pink tone.

Piranha3
Piranha3  have blue-colored scales and green-colored fins. Their arms and face is of light-bluish tone.

PiranhaSP
PiranhaSP  have grey-colored scales and pink-colored fins. Their arms and face is of light-purple tone.

RarePiranha
RarePiranha  have pink-colored scales and blue-colored fins. Their arms and face is of greenish tone.

RarePiranha2
RarePiranha2  have yellow-colored scales and grey-colored fins. Their arms and face is of yellow tone.

Trivia

 * Piranha and Handy viruses are the only viruses to ever reappear after their blacked-out chip image status, unlike viruses such as Minelayer, Mollusk, and Tornado, that appear only in the first game, and never show up again, resulting in a permanently blacked-out chips in the subsequent games.