I need your help to buy a camera. I need it for taking photos of my underwater pets through the tank. I need one that will not blur and takes the photos quickly as they move a lot. The lighting isn't the greatest either really being water.

I have no idea what it all means. People are talking to me about macro but I don't know what this is.
I want to spend less than 200 really. Obviously the less the better.
I have photos ive taken on my iphone of my pets that i can put on her if you want so you can see how there coming out. Thanks in advance