No one gives thanks to StarClan for prey and stuff.
Not sure about this, but StarClan can be rarely mentioned. Only when someone died or used like "Great StarClan!" or something.

* Eh, depends on how important StarClan is to your character/Clan, or if it exists at all. You can have a Clan that can respect StarClan while largely believing they have the most control over their surroundings and fate. You can have a Clan believing that StarClan can give as much as they can take away, and so saying gratitude is a must.