Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Do not buy fish that is in the water, for that is a sale involving uncertainty (gharar)."
Ahmad recorded it both "mawquf" (as the Companion's own statement) and "marfu'" (attributed to the Prophet), and al-Tabarani recorded it likewise in al-Mu'jam al-Kabir. The narrators of the "mawquf" narration are the narrators of the Sahih; among the narrators of the "marfu'" narration is Ahmad's teacher Muhammad bin al-Sammak, and I have not found anyone who gives his biography; the rest of its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب البيوع / 6353
Hadith Gradingمحدثین:مرفوعاً ضعیف
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (10491) اخرجه احمد فى المسند، (3676) ، أخرجه مسند أحمد برقم: 3667، وأخرجه المعجم الكبير للطبراني برقم: 10491»