Hi Hector,
When you say you and the others started feeling weird things after the fish tank broke, what do you mean? What were the feelings/sensations?
Also, and we have to consider logical reasons for things that seem paranormal, is it possible that the fish tank glass had a weak spot, causing it to explode in that way? I'm thinking that it the nature of a glass break when water pressure is behind it. Anyhow, just something to consider.
The disappearing and reappearing items might well be ghost related. They like to take things. You can always ask for them to put them back, just do it nicely. Never yell or get angry, that can make things worse.
Do you know what the history of your house is? This can sometimes help pinpoint why it's haunted. Try doing some research if you don't know anything about the house or the land it sits on.
Taking pictures is a good start. =) Just be sure to follow the protocols while taking the pics.... no smoking, no camera strap, etc. These things can produce false anomalies.
Keep us posted!
Kell