Adding new fish

I want to add new fish to my tank just worried about adding fish as my fish are happy and are doing well . How can I add fish with out bring diseases to make tank and making my dicus sick

one thing to do is set up a quarantine tank for new fish so they can be monitored and treated for any disease for at least two weeks prior to adding them to your main tank.

Use the search engine to locate a multiplicity of threads on the QT process for acquiring new fish. There's a bunch of info already available there mate :)