Allow this pedant to quibble. In regard to snakes, “poisonous” refers to substances that cause acute symptoms of at least distress upon ingestion. No snakes are “poisonous” in this way. Even snake venom can be swallowed, providing it does not encounter an open cut or wound. Many toads and salamanders though are poisonous.
“Venomous” refers to the ability to project a poison in such a manner as to damage another animal. “Venomous” snakes may bite to inject venom, bite to drip venom into the wound channel, or spit venom (often at a victim’s eyes).
“Fangs” refers to the modified dental equipment used to deliver venom. Some venomous snakes have long fangs (relative to the length of their other teeth) e.g., vipers and pit vipers. Others have short fangs (hardly longer than their other teeth) e.g., cobras.
Some non-venomous snakes have a mouthful of really lo-o-o-n-n-g teeth, e.g., tree boas. Try really hard not to be bitten by a large one!
Lots of variation. Some bites from non-venomous snakes are extremely ugly (e.g., aforesaid tree boas, Indigo snakes). Bites from “black snakes” (regionally, many different snakes bear this common vernacular) are usually among the less noteworthy.
Idiots persist in their own mythologies of snake “lore”, which leads to far too many unnecessary snake deaths. Case in point-- the OP.