I live in a fairly small town in a fairly rural area, and PetCo is the only practical option for saltwater fish. The only LFS
still open discontinued marine and reef livestock. I'm lucky enough to live only a couple hours from "Wet Pets", in PA, which is the best LFS
I've ever seen. I usually go there for anything rare, delicate, or expensive, but it's just not practical for me to spend that much time driving. PetCo is my only option.
I realize the general impression is that PetCo is that it's the worst of the chains, and barely a step above WalMart, but this depends largely on the employees (who are given a certain amount of leeway). Walmart is a foul fish graveyard where you can count on seeing dead mollies three deep on the bare floor and brackish water puffers with their fins rotted off puttering around a tank full of ich-covered goldfish.
By comparison, my local Petco (in Morgantown), hired only active aquarists to work the aquatic section, and I know they are competent because they've given me helpful advice on medication and livestock compatibility. Our Petco does quarantine sick fish (albeit together), and they refuse to sell fish that appear sick or injured. I've never seen a dead fish floating in the tanks or an injured fish being bullied by a larger fish. If you are sensible about observing the behavior of the specimens you want and come back over the course of a few days to monitor them, it's a safe as any other store. Even the inverts in their seperate section look healthy, and one colonial mat I've been thinking about has grown maybe a third again it's original size since it's been in their tank.
On the other hand, the nearby Fairmont, WV local independent store "Animal Kingdom" has the most dismal, plague-ridden, unethically overcrowded aquariums I've ever seen (outside WalMart), including adult Oscars sharing a ten gallon aquarium they literally couldn't turn around in and a Regal Blue Tang whose lateral line and face were so diseased they seemed to be corroding before my eyes.
I guess my point is that so much of a LFS
's quality is based on the people who run it, and dedicated and knowledgeable workers at a chain store can make it a lot nicer than an independant store run by bored, lazy, and unethical people.
<The proceeding opinions are my own and do not reflect the management of AquariumAdvice.com. Or Petco, for that matter.>