[ Rin is speaking the language of Sakura's people which makes perfect sense since they're both medic-nin! Not that she can tell that from her initial appearance and it's very much likely that the same could happen to the other seeing as Sakura's own hitai-ate is missing and in it's place is a red headband to keep most of her hair pulled back. ]

It varies from Pokemon to Pokemon really so it might take you a little while longer to figure out what makes yours tick. For example, I've got one that feeds off electricity so I have to let him stick near a socket every so often or else he grows weak.

As for the poisonous substances, the best you can do is carry antidotes. It seems as though it doesn't do more than make us sick as humans, but it can cause a Pokemon to black out. You'll likely want to pick up some more too because once your entire team blacks out, you're in real trouble.