I am using the following code to make a 3D vector plot.
VectorPlot3D[{
x (1 - x) - x*y,
y (1 - y) + x*y - y*z,
z (1 - z) + y*z},
{x, 0, 1.2},
{y, 0, 1.2},
{z, 0, 1.2},
Axes -> True, AxesLabel -> {"x", "y", "z"},
VectorColorFunction -> "Rainbow",
VectorScale -> {0.05, 0.7, None}]
This makes a bunch of vectors, but the entire vector is colored. Is there a way I can use VectorStyle or another option to make each vector have a black outline, but have the inside of the area filled in with the appropriate color?