def get_positions(target, fish_list):
    """
    We want to get the positions (and the list of corresponding fish) of 
    every fish except the target fish.

    Parameters
    ----------
    target : Fish
        Target fish.
    fish_list : list
        List of every fish.

    Returns
    -------
    pos_list : list
        List of positions of every fish except the target fish.
    exc_list : list
        List of every fish except the target fish.

    """
    pos_list = []
    exc_list = []
    for fish in fish_list:
        if fish == target :
            pass
        else :
            pos_list.append([fish.position[0], fish.position[1]])
            exc_list.append(fish)
    return pos_list, exc_list