A very fishy question...Tuna types and mercury?

I have alot of questions about Tuna, I know some people don’t like it but lately I can’ t get enough. I know this sounds like a joke but I could literally eat it a few times a day. I am sure it is just a phase and I will get sick of it eventually.

I read that Tuna has a lot of mercury in it though, is there a safe level of what I can and cannot eat?

What is the difference between albacore and all the other stuff. I don’t like eating it in oil, only water.

What does to much mercury do to you?