Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
All kinds of seafood are permissible except for that which are specifically prohibited by a text or harmful for health.
Answering your question, Dar Al-Ifta Al-Misriyyah, states:
All kinds of seafood are permissible except for that which are specifically prohibited by a text or harmful for health. This is based on the general implication of the words of God, {It is lawful for you to hunt from the sea and to eat seafood.} (Al-Ma’idah 5:96)
Also, Prophet Muhammad (peace and blessings be upon him) said about the sea, “Its water is pure and its dead animals are lawful to eat.” (An-Nasa’i)
We also read in the Quran:
{[Prophet], say, ‘In all that has been revealed to me, I find nothing forbidden for the people to eat, except for carrion or blood spilled out or the flesh of swine—for indeed, it is impure—or it be that slaughtered in] disobedience, dedicated to other than God.} (Al-An`am 6:145)
Therefore, the principle in eating seafood is permissibility unless it is proved otherwise.
Almighty Allah knows best.
Source: Dar Al-Ifta Al-Misriyyah