ronrca

A few more fish will not hurt depending on your filteration. You could get away with putting 100 neons in a 30G if you had the right filteration. Of course it would get a little crowded. Another consideration is surface area of the tank. I usually calculate so many square inches of surface area per fish depending of the species unless you have plants. I usually like to have less fish in a tank because then I dont have to worry about overcrowding or other disasters to happen. In my 30G, I had 10 neons, 5 tiger barbs and 2 blue rams. Never had any problems.