  We study linearized stability in first-order relativistic viscous
hydrodynamics in the most general frame. There is a region in the parameter
space of transport coefficients where the perturbations of the equilibrium
state are stable. This defines a class of stable frames, with the
Landau-Lifshitz frame falling outside the class. The existence of stable frames
suggests that viscous relativistic fluids may admit a sensible hydrodynamic
description in terms of temperature, fluid velocity, and the chemical potential
only, i.e. in terms of the same hydrodynamic variables as non-relativistic
fluids. Alternatively, it suggests that the Israel-Stewart and similar
constructions may be unnecessary for a sensible relativistic hydrodynamic
theory.
