Rachada area is more catered towards upscale clients, but places that have fishbowl charge similar pricing to other places that have fishbowls. Sideline and VIP is where price typically jumps up and some places will charge extra for foreigners but may come down with bargaining or if you come with friend.
Tell cabbie to take you to "Ra-CHA-da", if he doesn't understand try "NAT-a-lee" (Nataree, r and l is interchangeable in Thai, that is why there is a "Halem" on Petchaburi)

From north to south on Ratchadphisek Road

CopaCabana - Went in this place several times. Never really impressed with the selection. Even sideline, superstar, and VIPs a big yawn when I went in. Still might be good for a look if you are at Poseidon as is right around corner.

*Poseidon - Like Poseidon a lot. Fishbowls on second floor affordable with large lineup. Many cute ladies. Third floor is must stop for those seeking top looking ladies in Thailand. In January, 4 Thai edition Penthouse models currently working. Price higher at 3300-5500 baht ($79-$131) but not too bad for Penthouse models. Photos in binders are available. Booking is recommended but may want to attempt to see lady in person before booking. Sometimes photos hide minor flaws or lady may have attitude. Had good experience with Poseidon lady and submitted photos. Attractive face, excellent body, friendly good service but no kissing. I looked for Russians but they said no longer available due to government intervention end of November.

VIP - Went in but not memorable lineup or experience. Typical fishbowl I guess. Will try to check again next time.

HiClass (located behind buildings, go to Emmanualle and walk right to find) - Some cute ladies, decent lineup. Nice sideline ladies but very few. Had Russians hidden in back room, but had to be persistent to find. (was actually persisting to see if more VIP in back but there was misunderstanding) Chose girl that ended up being a little overweight on my side of fishbowl. (yes, even slight overweight is tough find in Thailand) Room was tiny and service was ok. Didn't really like experience compared to other places so will likely not use HiClass unless find stunning lady next time.

Emmanualle - Nothing special about fishbowl. OK sideline and VIPS but not as nice as Poseidon, Nataree, and Mirage. Didn't find any ladies to justify prices.

*Nataree (Right side) - My new favorite place in Thailand. Great lineup of beautiful ladies at very affordable prices. Some nice sideline but fishbowl shines. Three ladies I sampled spoke Chinese for some reason. All three wanted double shot in 2 hours. Will be one of first stops on next trip.

Nataree (Left side, there are two places labeled Nataree massage with place in between) Mostly traditional massage with sidelines that provide full service. Sidelines here are like fishbowl elsewhere.

Subway - Same as VIP above. Must have been too excited going between Nataree and Mirage.

*Mirage (Walk half block down Soi to left of Nataree/Subway to find Mirage on right) - Must stop for some top looking ladies. Booking recommended. Fishbowl has above average lineup of ladies as well. Did not like papasans here and 5th choice sideline lady I chose was boring (4 previous choices were booked), but some look so amazing that I'm willing to give two or three or four more chances.

Nadia - From what I saw was traditional only and poor selection of ladies so I walked out.

Ceasars - On other side of street. Didn't check, will try next time.