Primarily, one is only allowed to consume fish from the water creatures according to the Hanafi school of thought. (Al-Hidayah Vol. 7 Pg. 150 - Bushra) 

Prawns: In brief, due to the difference of opinion in categorizing prawns (is it from fish family or not?), our ‘Ulama have advised us to exercise caution and abstain from eating prawns as this is also the demand of Taqwa, which is the best and safest option for a believer. 

However, one should not reprimand others who consume it, and should not accuse them of consuming Haram as some ‘Ulama have permitted the consuming of prawns. 

Calamari:

It is impermissible to consume calamari since it is not from the species of fish. (Fataawa Darul Uloom Zakariyya Vol. 6 Pg. 271-272) 

AND ALLAH TA'AALA ALONE IN HIS INFINITE KNOWLEDGE KNOWS BEST

ANSWERED BY: Mohsin Khan 

Islamic Date: ٩۱ ذو القعدة ١٤٤٠ 

English Date: 22 July 2019