both poisons and venoms are toxic substances (toxins) so the venom delivered by the spines would technically be toxic, although idk if you could describe the spines themself as toxic so I guess venomous would work better from a biological pov
also, correct me if I'm wrong, but I'm pretty sure all toxins reach our bloodstream regardless of if they're poisons or venoms. a better way of comparing the two would be to compare how they enter our bodies. poisons are injested into the body, either through consumption, inhalation or absorption through the skin, whereas venoms are injected, either through a bite or a sting
this is what I had in mind, I maybe didn't make that clear. the idea was that if a nicheling with this gene was attacked by say, a bearyena, the bearyena would end up getting scratched by the spines and the toxins would enter the body that way