Part of the reason most petco/petsmarts do not have knowledgeable employees, is people that ARE smart about animals are to busy screaming how horrible the stores they are to actully work at one and try to make it better.
I sceamed and yelled untill every employee at the petco I worked at knew what the cycling process was, knew what were proper fish to sell, ect ect.
I agree with those saying coperate is the biggest problem, Its true that when fish come in under wrong skus, we still have to leave the incorrect sku and sell it as such. Its also hard to control what your allowed to carry at the stores. If I had my way there would be no channel cats or irridesent sharks in the store. But because channel cats are a "big seller" we have to have them. I constantly fought with coperate about selling iguanas (3 yrs later they discontinued selling them in our district). There was also the fun time peroid where I kept getting in trouble for telling the customers the painted glassfish would die if they bought them, and that it was basically tourtue that they were injected with dye. Thank goodness they stopped selling those.
The worst part about working at a chain store and knowing what you are doing, is the fact you cant really refuse a sale unless the person implys they are gonna kill the animal on pourpose. So although you can explain over and over, why the fish is not gonna make it in whatever they are trying to do, you still gotta sell it.
My particular store is going to hell due to a new horrible manager, so i quit this week, which is good because i think i might have went off on the next customer who tells me that goldfish do great in a 2gal bowl and even live a whole 9 months.
best thing about working there, was the free fish I got from people coming in that didint want them... 12" RTC, Tilapia buttikoferi, two adult Leporinus fasciatus, and an adult Polypterus endlicheri
Maybe the stores do not want to hire the knowledable people because of the constant backlashing the higher ups go through.. it is and always will be about money in this industry as well as any other animals being sold.. look at the puppy mills.. that must be extremely hard to turn the other cheek.. 
Most people who care too much would not be suitable for the job.. you either have to be naive or callous to not have it bother you.. never thought of all the emotional things that go into being an LFS store employee.. 
