I work in an LFS (actually it's a chain, but our store is one of the better ones in our area, better even than some non-chain lfs. IF all our stores followed the necessary rules for keeping up our animals and/or tanks, they'd all be great, but I know not all our stores do..., oh and we're way better than our competitor chain), and I"ve gotten customers who come in with a new take on this rule that is even worse. They say "Now, the rule is, one fish per gallon of water, right? So, I can put ten fish in this ten gallon tank?". YIKES!! The bottom line most of our basic fish newbies want to know is how many fish they can put in one tank. (usually, how many fish can I have in this 1 gallon tank?). So, I say, actually, the rule you are thinking of is most likely "one inch of fish per gallon of water" and this is a huge generalization and doesn't work in all circumstances. I also explain that many fish have a minimum tank size required. And, that even though there is a minimum tank size, it doesn't mean you can only put one of those in that size, but rather you can (and often should with schoolers) have many of them in that size tank. (and/or other suitably tempered fish). (also, the one inch per gallon rule is much more for bioload(and still not always helpful, though usually fine for smaller thinner schoolers) rather than temperment, and that also must be taken into account) We reccomend that beginners start with no less than 20gallons, though many want to start smaller and get larger only if they have luck keeping fish alive. It's hard to get them to understand that it is actually easier to keep fish alive in a larger tank. (of course, we also have to explain that larger tanks are really not a huge pain to care for, because you don't want to remove all the water and wash all the gravel regularly...). Most of the time, our newbie customers feel as though we are trying to sell them more than they need with larger tanks and fancy filters. However, those who have done some research know we are setting them straight and usually are happy with our advice. We do get newer associates that have less fish experience than those of us with 7+ tanks, they however, will explain some of the basics, and say "I don't know" if they don't know an answer. They also don't hesitate to find someone more experienced to answer a question. So, at least we try very hard (with few exceptions, but those tend to weed themselves out of our business) not to provide misinformation. IT just gets tough to correct all the myths out there, and often we do have to sell fish to less than ideal environments. (though for really bad situations, we can say NO.).
So, for someone who wants to put one fish per gallon, getting them to think about size of the fish (and not just current size, but future size as well) is a major breakthrough.
If everyone would just do their homework :read: , we'd be far better off!
Emily