Dear Anirban,
Angaraka Dosha is nothing but mangal dosha, and it is termed when mangal or Mars will start creating problems in your married life. In your case, mangal is fine in 3rd house whereas Ketu the southern node of moon is creating a problem in your blood. Giving out infections and blood related diseases.
Yes, it will be better if you wear Cats Eye gemstone to reduce Ketu’s ill effects on Mars. Or instead you can wear Coral to strength Mars, which I find not so good solution for your health related problem.
I can see you have killed or seen during anybody else killing snake or your dad side some body / your dad himself had killed a snake especially king cobra. By which you will encounter this particular dosha.
For which sarpa samskar, this ritual is performed when a person dies in your family and 3 days samskar is done; at this same time, this pooja will also been performed. They do the idol of sarpa or snake then they do the kriya karm as per the rituals. Its basically done in all Snake awakened placess like Kukke subramanya in south (where famous legend Sachin Tendulkar had performed the same puja in this place).
GOD BLESS!!!
Srinivasa Temkar