1. Drop the flaming or infractions will follow.
2. Stop saying petco keeps, or fish store keeps. They also put 400 fish in a 30 gallon. It is a temp holding tank. Plus most fish stores do keep them in different ph... wonder why petco and petsmart and most pet stores have people remove dead fish all day. We are making perm. homes for our fish. Saying but petco or fish stores does, is like say well they ship fish in bags for Africa, so I can keep my fish in a bag in my living room. No you can't (and fish live).
3. Yes mixing fish is not a good plan, does it work some times yes. Often no... Feel free to share you experiences, but remember people new to fish keeping read your posts as well.
4. Share all the information people! What is the stock list, tank size, filtration, and etc.
5. Get along...