I agree somewhat with things that have been said here .....BUT.....
It is hard to research when you don't know what to research. Yes, I did research my fish before I went and bought them but had no idea that cycling existed, even though I read many sites online (not this one obviously)....If enough sites tell you to add fish after letting water stand for a week then thats what you will do and is what I did.
Its hard likening it to buying a house. I mean, everyone knows the house has to be structurally sound, good value etc. Not EVERYONE knows about nitrogen cycles etc. Reading about the types of fish and what goes well together is one thing but knowing to cycle yur tank is another.
When I bought my first fish it was 3 days after adding water. the LFS man asked me "Is your water clear?" and I said "Yes" and he asked me what fish I would like and I replied "platies and tetras" and he sold me 6 platies, 6 neons and 6 glolight tetras. For a brand new setup that hadn't even started cycling. That was in the middle of summer. My tank had peak levels of ammonia and nitrites on Christmas Day when the temperature soared to 42degC...I lost a few fish that day...weird thing was that the fish tank was my christmas present. Yeah, happy christmas, all the fish are dying.
The same LFS man also told me that no matter what I read UGFs were the best filters a tank could have. He also told me that platies will not eat algae tablets (imagine!!!!) and that any plants will grow in my "bright" tank. I say bright since the tank DID look bright back then. Suffice it to say that all my plants were dead in a very short amount of time (I had 20watts over a 30gal tank)....he had sold me swords, val, hygro and some others I can't remember.
Research, yes, but its not that simple.