I now have all four plants and the snail. In the selling tank, I also have the shell, the diver and the coral. I have all three levels of research in both food and environment, but still only have the first level in advertising.

I have sold anywhere from as little as four fish to as many as 21 fish without any problems so far. Oh, and I don't know if it matters but I now have (and have sold) the first three magic fish.

I had the first four magic fish when I started having problems last time, so I think I will wait on buying the second level of advertising until after I have (and have sold) the fourth magic fish.