Yes we have all lost fish by:
1. impulse buying and then trying to find out what it eats and its other needs.
2. buying a fish before we see it eating in the lfs.
3. buying a fish that is not 100% healthy because it was there was only one left in the lfs and we liked it or justifying the purchase cause we would `cure it` (after all our tank is healthier than the lfs` `we are going to `save that fish`)
4. buying a fish that deep down we know it is a difficult fish to keep but we believe that one or two posters `who have had them for months and it is healthy and eating`. Again, a justification.
5. buying too many fish at the same time. (only a newbie mistake)
6. buying a fish that requires a large tank `tangs`, a mature tank `mandarin gobies`
There are many good books like Robert Fenner`s The Conscientious Aquarist, websites like
www.wetwebmedia.com and there are many experts on this forum on certain fish and `seasoned` reefers who have already been through it all.
There is a learning curve but we should not be trying to reinvent the wheel or challenging what we already know.
We are all learning!