Tanker is right. That's WAY too many fish for a 6 or 8 gallon tank (had to get google to do the conversion
). I'd spend some time with Craigslist or the local version thereof. I got my 55g tank (approx. 200 l) for free. It's not in the best shape. It has some scratches. But it was free.
I'm not looking at the compatibility factor with your fish right now, though you do have some issues and I'd do some reading. If you wanted to keep that number of fish in that general size range you'd be looking at something in the 100 to 250 l range. I think (without knowing your market at all, or the exchange rate perfectly) that you could find something like that used for 50 pounds if you shop around some.