Well, there is The Pet Works but I am not the biggest fan. They have locations in Olympia and Longview. I have gone in several times and seen dead fish. I do know that they will qt their tanks if something is wrong. Each tank runs off of it's own sponge filter.
There is Kaija's in Chehalis. I really like them, even if it is a bit far for me. They are willing to special order fish for you and will even treat them for 3 days after delivery. The staff seemed knowledgeable and very helpful. I think I spent an hour talking fish with them. I did not see any dead or sick fish. My most recent purchase of Cardinal Tetra and my female BN Pleco are from here. They tend to be about 30% more expensive but have healthier stock.
I would avoid Pioneer West in Chehalis like the plague. I saw several tanks infected with Ich and the staff didn't know too much about the stock. I saw several very unhealthy fish. I left as soon as was polite.
All of these being said, the fish departments are pretty small in all of these stores since they are full pet stores and not just aquarium stores. I usually take a trip to Oregon when fish shopping, since I am only an hour away from Portland. Out there is The Wet Spot and World of Wet Pets. Wet Spot is huge and wonderful, but has the worst parking ever. The World of Wet Pets has a smaller selection, but is easier to access. I like both places.
