Basically all the stores in this thread are within an hours drive of Torrance.
Here is a list of stores in the south bay harbor area.
Seven seas - located in san pedro. SW/FW. The quality is better than ive seen in most stores as far as exotic corals. They do not frag and sell corals whole listing as $200-$300 for large rare corals. They are VERY, VERY pushy and will sell you as much as you can carry. You will get suckered.
Neptunes reef - located in torrance, fish are always unhealty, staff is rude ecspecially the owner. Very small reef tank, nothing special.
Pacific Reef - located in harbor city, this was the worse store i have ever been to. The coral selection is embarrassing. Was actually in there today and seem to be re-doing the whole place. The fish selection was sad but now all fish were healty and very large selection. Will go back next week as they are trying real hard to clean up
Age of Aquariums - located in long beach, very clean store, great dry goods selection, good fish selection and will Special order for you. Nice display tank, nice coral and coral frag selection. Staff is very nice.
Jims exotic fish - located in el segundo, new freezer for frozen food which includes a large selection. Small selection of corals and fish. Competitive prices.
Aloha tropical fish - SW is only 50 cents a gallon if you get the owner which is a nice lady. If she likes you, you can talk her into lowering prices to wholesale. Will also special order for you. Available stock usually is bad, there is only a nano cube tank of corals to choose from. Usually different selection so somebody is buying.
Pasadena Tropical fish - good selection of corals and fish. Fish are usually healthy. Owners are Thai and very nice. A little overpriced but probably because they are the only store around in pasadena.
There is another store in pasadena on lake ave near kfc but is rundown and people are rude. SW selection is usually empty. No corals.
Petco - yes really. There is a petco in pasadena right when you get off the 110 freeway. Surprisingly decent SW fish selection. Staff are morons except for the fish guy. Decent coral tank which was always kept up. I havent been there for months so sorry if it has changed.
Aquatic Outlet - located near LAX, they are changing the name to aquarium world. Staff is not the friendliest but they do get their fish before most stores as the wholesalers are a block away so you will usually find the healthiest fish at a decent price when they have a large stock. You can find great pieces of live rock in all sizes including super large 30lbs pieces. Corals are always dying as they keep changing and moving their tanks.
Reef hot spot - i thought this was my own discovery and i told no one about this place. They are a wholesaler frag store open to the public. Great frag selection, decent prices. Hard to find try not to get hit by a car.