2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/226180It is proven that Gaussian operations are of no use for protecting Gaussian states against Gaussian errors in quantum communication protocols. Specifically, we introduce a new quantity characterizing any single-mode Gaussian channel, called entanglement degradation, and show that it cannot decrease via Gaussian encoding and decoding operations only. The strength of this no-go theorem is illustrated with some examples of Gaussian channels.4 pages, 2 figures, REVTeX4Quantum Physicstext