It's best to thaw frozen proteins, still in their wrapping (or a ziplock bag) in cold, not hot water, still refrigerated, so they thaw evenly. Thawing in hot water risks creating an environment where bacteria can grow.
I would feel confident eating it. I don't think that half-an hour is long enough for the bacteria to multiply significantly. Also if you baked it until flaky that should have been enough heat to destroy the bacteria. The recommended temp to cook salmon is 145 degrees and salmonella (an example of a food borne bacteria) is killed at 140. That said I would eat it sooner rather than later.