  Kinetic simulations have demonstrated that three-dimensional reconnection in
collisionless regimes proceeds through the formation and interaction of
magnetic flux ropes, which are generated due to the growth of tearing
instabilities at multiple resonance surfaces. Since kinetic simulations are
intrinsically expensive, it is desirable to explore the feasibility of reduced
two-fluid models to capture this complex evolution, particularly, in the strong
guide field regime, where two-fluid models are better justified. With this goal
in mind, this paper compares the evolution of the collisionless tearing
instability in a force-free current sheet with a two-fluid model and fully
kinetic simulations. Our results indicate that the most unstable modes are
oblique for guide fields larger than the reconnecting field, in agreement with
the kinetic results. The standard two-fluid tearing theory is extended to
address the tearing instability at oblique angles. The resulting theory yields
a flat oblique spectrum and underestimates the growth of oblique modes in a
similar manner to kinetic theory relative to kinetic simulations.
