I just got a new 20g about a week and a half ago. A couple days after I set it up i bought 5 tetras, 2 black mollys and 2 african dwarf frogs. Over about a weeks time 4 of the tetras died and 2 of the frogs died, one of my friends told me it was because i didnt waite for my tank to get established. I was just wondering when it would be safe to get more fish. Thanks