Yes, red snapper is considered halal according to Shia Islamic dietary laws.
Based on Shia jurisprudence, fish that possess scales are considered halal. Red snapper, being a fish with scales, falls under this category. Therefore, Shia Muslims can consume red snapper without any religious restrictions. The presence of scales is the key determinant for the permissibility of fish in Shia Islam.
Therefore, based on this understanding, red snapper is permissible (halal) for consumption by Shia Muslims.