I'm sorry to hear about your loss.
That would be a personal nightmare for me, so I could only imagine what you are going through. Unfortunately in our society, we will only see this type of activity continue to grow unless we become more proactive as a society.
As for your insurance claim, I'd start to make a list of items missing now. For each item, try to find a reciept, and if you can't find a reciept, try to contact the store you purchased it from to see if they can print you a reciept. Next, try to find any pictures of the items that are missing. Try to find old pictures of your place and compare them to your place now to see if anything is out of place. A video is even better if you have one. Try to do things that you have done in the last 6 months as well. You will be forced to use things from around your place then, and can find out if they were stolen. You'd be surprised how many customers have found out that some items were missing from a theft 6 months after the fact. As for the actual corals you have lost from your tank, I would make a list of what you had. Some companies may cover this type of loss, and if they don't and want to question how much money you have in your marine equipment, you can show them how much the livestock was worth that the equipment was keeping alive. Lastly, I'd keep a notebook and pen with you at all times. That way, if you think of something that may be missing or they might have taken, you can write it down and check.
Good luck, and if you have any questions, feel free to write me.