There are many commandments regarding food in the Torah (known to Christians as the Pentateuch). Among them, Jews are commanded not to eat anything which lives in the water, unless it has fins and easily removed scales. Consequently, prawns, as well as shrimp, crabs, calamari, etc., are forbidden. Swordfish and sturgeon have fins but no scales, so Jews don't eat those either. For more information, look in The Bible under Leviticus 11: 9-12 and Deuteronomy 14: 9-10.
prawns eat plankton, tiny creatures in the sea
no
yes
Yes, they do.
No. Its meat
Yes, it's safe for dogs to eat prawns or shrimp.
No, unless it is artificial flavoring. Prawns and other shelfish are not kosher. The only kosher seafood are fish that have both fins and scales.
they eat prawns
yes
You are perfectly able to have ice cream after prawns. There are no limits to when you are and are not allowed to follow-up your seafood meal with a frozen desert. That said, you may not want to mix the flavors.
Mixing meat and dairy, and shellfish and pork are NOT considered healthy.
pregnant women can eat dry prawns