I would blame the pet store, at least partially. When you go buy a car or a dishwasher, you figure that the people selling the stuff are professional and knowledgeable about their products. When you are new to the hobby ou think the same thing about the fish store people. It's only until later on when you've been burned that you (all of us) eventually realize that their only goal is to sell you something/anything.When I first started out with fish I was in the pet shop about twice a week for around 6 months asking questions and getting all the knowledge that I could and it was under their advice that i had 2 fan tails in a 3gal tank and again they told me that i could add several more fish to my 35litre one. I have been acting on their advice from the start so do you think that they are giving me the wrong advice on everything??
I do around a 30% water change once a week, vacume the gravel and do a general clean/tidy once a week. I use the API master test kit and the readings are normally bang on, got an ammonia spike after adding the new fish but it calmed down after a few days.
I am going to go back to the pet shop (Pets at Home) and let them know what has happened so hopefully they can prevent it happening to other customers.
Sometimes it's not even a matter of them trying to trick you - they reallt don't even know themselves. But whether or not they give you the wrong advice out of ignorance or greed, you'll still be back there buying more fish when these die, because you thought they were being nice.
Being here and reading people's stories etc. I've learned to do research on anything I buy now. I don't care it if's a fish, or a radio, or cat litter.