There is always a lot of controversy in eating prawns, mussels, squid and octopus. Can you please elaborate which ones you can eat and the reasons for the ones you cannot.
In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
According to the Hanafī school of jurisprudence, from the sea creatures, only that which falls under the Arabic term samak is permissible to consume. Samak is commonly translated as fish.
There is a difference of opinion in regards to the permissibility of prawns.
The origin of the difference of opinion is due to the uncertainty in the categorisation of prawns. Some scholars consider prawns to be samak, whilst others do not. Those scholars who consider prawns to be samak are of the opinion that prawns are permissible. The scholars who do not consider prawns to be samak hold the view that prawns are impermissible.
Some of the scholars from the Indian subcontinent who are of the opinion of the permissibility of prawns are:
a)Maulana Ashraf Ali Thanwi rahimahullah
b)Mufti Abdur Raheem Lajpuri rahimahullah
c)Mufti Mohammad Abdus Salaam Chatgami rahimahullah
Some of the scholars from the Indian subcontinent who are of the opinion of the impermissibility of prawns are:
a) Maulana Rasheed Ahmed Gangohi rahimahullah
b) Maulana Khaleel Ahmed Saharanpuri rahimahullah
c) Maulana Rasheed Ahmed Ludyanwi rahimahullah
There are two reliable opinions with respect to the issue of prawns. Taqwā would demand that a person refrains from eating prawns, though there is leeway in consuming it.
Mufti Rasheed Ahmed Ludyanwi rahimahullah in Ahsanul Fatāwā mentions that there are three features in fish:
Mussels, squid and octopus do not have all the features of fish; therefore they will not be regarded as fish. Hence, it is not permissible to eat mussels, squid and octopus in the Hanafī school of jurisprudence.
And Allah Ta’āla Knows Best
Mufti Faraz Adam al-Mahmudi
 (وَلَا) يَحِلُّ (حَيَوَانٌ مَائِيٌّ إلَّا السَّمَكُ) (الدر المختار ج 6 ص 306 أيج أيم سعيد)
 أحسن الفتاوى ج 7 ص 394 أيج أيم سعيد