I don't have one set on my tank, (going to now) but I use the d-link cameras off of amazon for my outdoor livestock for when i'm at work, away, etc. I can pull up the app on my phone, see a live feed, hear sounds, and with one of the ones I have I can move it around which is great.
I use this Uokoo IP camera and have it sitting on the desk right next to my tank. The app on my android works very well and easy to setup, allows me to pan 360 degrees up and down, 4x zoom, and has a night vision. They also sell this camera in a 720p version for $30 dollars less. I have it hardwired to my router, but it also supports WiFi.
If you are a little more on the technical side and don't want to only use the mobile app, you also have the option from your home router to give the camera a static IP and port forward the address. This allows you to use their web-based applet from any browser.