Hadith: Two kinds of dead meat and two kinds of blood have been made lawful for you. The two kinds of dead meat are fish and locusts, and the two kinds of blood are the liver and spleen

عن عبد الله بن عمر رضي الله عنهما قال: قال رسول الله صلى الله عليه وسلم : «أُحِلَّتْ لكم مَيْتَتَانِ وَدَمَانِ، فأما الميتتان: فَالْجَرَادُ والْحُوتُ، وأما الدَّمَانِ: فالكبد والطحال».
[صحيح] - [رواه ابن ماجه وأحمد]

‘Abdullāh ibn ‘Umar (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Two kinds of dead meat and two kinds of blood have been made lawful for you. The two kinds of dead meat are fish and locusts, and the two kinds of blood are the liver and spleen."
[Authentic hadith] - [Narrated by Ibn Majah - Narrated by Ahmad]

Explanation

Ibn ‘Umar informs us about two Fiqhi rulings related to the lawfulness of eating some things: the first is the lawfulness of eating dead locusts and fish, and the second is the lawfulness of eating two types of blood, which are the liver and the spleen. These two rulings are exceptions to the prohibition of eating dead animals and blood.