  Spinel Cobalt Vanadate CoV$_2$O$_4$ has been grown on (001) SrTiO$_3$
substrates. Using torque magnetometry experiments, we find that the previously
observed temperature induced anisotropy change, where the easy axis changes
from the out of plane [001] direction to a biaxial anisotropy with planar <100>
easy axes, occurs in a gradual second-order structural phase transition. This
work characterizes this transition and the magnetic anisotropies in the (001),
(100), and (-110) rotation planes, and explores their field dependence up to
30~T. Below 80~K, hysteretic features appear around the hard axes, i.e., the
out-of-plane direction in (-110) and (010) rotations and the planar <110>
directions in (001) rotations. This is due to a Zeeman Energy that originates
from the lag of the magnetization with respect to the applied magnetic field as
the sample is rotated. The appearance of the hysteresis, which persist up to
very high fields, shows that the anisotropy at low temperature is rather
strong. Additionally, field dependent distortions to the symmetry of the torque
response in increasing applied fields shows that magnetostriction plays a large
role in determining the direction and magnitude of the anisotropy.
