  We carry on a general study on non--static spherically symmetric fluids
admitting a conformal Killing vector (CKV). Several families of exact
analytical solutions are found for different choices of the CKV, in both, the
dissipative and the adiabatic regime. To specify the solutions, besides the
fulfillment of the junction conditions on the boundary of the fluid
distribution, different conditions are imposed, such as vanishing complexity
factor and quasi--homologous evolution. A detailed analysis of the obtained
solutions, its prospective applications to astrophysical scenarios, as well as
alternative approaches to obtain new solutions, are discussed.
