Walls of Text incoming, I can offer a summary of any of the below pet stores if anyone requests.
Slither and Swim in West Haven. It's a small store, in a small plaza, with a small parking lot. Walking in, there's a bunch of cool reptiles and frogs and whatnot, I couldn't help but check out these badass lizards for a while before running to the fish section. The fish section has fish of all sizes, some tanks have some scary big fish (jumbo Pleco for $60 stood out to me) and other tanks have okay-priced fish you can find at Petco and whatnot. It was fun to look at everything and I don't recall seeing any dead or mistreated tanks. I went in to buy Christmas gifts, so I was looking for some cool inverts and plants. I got two Dwarf Orange Crayfish (CPO's) for $10 each, a nice Amazon Sword for $5, and a handful of Java Moss for $5. I wanted to leave with some driftwood (charged by the pound) and another Crayfish (I have a white one already, he had two white ones, a blue one, and an orange one). Alas, the Christmas season had me re-evaluating my shellfish (lololol) purchases and I just got my gifts and left. The owner was nice, he explained to me how to use Seachem Flourish / Excel and greeted me at the door. Oh yeah, they had a few saltwater displays with neat rocks and stuff, but I don't think any saltwater fish were for sale.
Aquatic Wildlife in Manchester. This place is amazing, but as a beginner, this place is probably not going to suit my needs until I decide to take up fishkeeping more seriously. They have a stingray / mantaray tank in the front, you're not allowed to touch because are you crazy, and that alone was awesome to see and experience. They have species that you won't find anywhere else. I only visited them twice when I first took up fishkeeping, so I don't remember what they had exactly. I just knew that their inventory was mesmerizing. Their fish all looked healthy and I noticed practically every single fish looking happy. They also stock many decorations that you wouldn't find elsewhere and they have a cool collection of rocks (also charged by the pound). Overall, this store carries great products, but everything is more expensive than usual. I'm a college student, I can't justify spending these amounts right now, and as much as I want to support this store, I simply can't. They also have some cool tanks for sale, I liked their nano tank selection, but again, too much $$$.
Wet Pets in Vernon. This LFS is great, probably the biggest livestock selection available in CT. I love the name of the store, too. Walking in, I had no idea which direction I wanted to go... In a good way! I could have walked straight and turned right, I could have walked all the way straight, I could have turned right immediately, I could have taken a left, there were so many interesting tanks that I felt like I'd be stuck in there for a while. I thoroughly enjoyed looking through all the tanks and observing the freshwater and saltwater species hanging out. They seriously have a LOT of tanks to look through. There's a good amount of saltwater tanks here, which was great. I got help from the owner (I think he was the owner) and he showed me the different types of shrimp they have. Bamboo, Amano, Red Cherry, and I spotted the Freshwater Prawns on my own. There's a great selection of food and their Betta fish were all looking pretty badass. There was something about the Betta display that I loved, but I can't remember why I enjoyed it so much. I can say that some of their tanks can use a quick scrubbing with a magnetic cleaner, but that's not a big deal. I only purchased some Java Moss from here. I'd go back if I had some spare time and money to bring home a nice fish, as everything here looked great.
Animal City in Vernon. Animal City is in the same plaza as Staples and Harbor Freight, so it's hard to miss. I love this spot, it's possibly my favorite LFS that I've visited. I can say this for sure, if there was only ONE store I would recommend you to visit, it'd be this place. They have so many different species, I can easily spend over an hour just looking at fish here. I've contemplated buying quite a few different fish from here, but I didn't want to use a heater in my tank, so I went with a Ryukin Goldfish. I've thought about two Fire Belly Newts ($7 each), a pair of Endler Guppies ($6 for a male and female pair I think, all I remember is that the price was better than anything I found on Aquabid), regular (brownish) Crayfish for $4, Red Neon Crayfish for $20, Electric Yellow Cichlid for $7, Tonguefish for $10, Emperor Botia for $17, or Kuhli Loaches for $3 or $5 (I forgot). I had to say no to most of these fish because the heater thing, my tank is too small for them or they're too weird (dat Toungefish doe... WTF). For any fish, you can buy 3 of a kind and get 10% off. They have a few standard tanks in stock with stands, many accessories and food, and live plants. They also have rocks and some driftwood, which is nice. I believe their rocks and driftwood are mostly overpriced, though. The owner is a great guy, very helpful and easy to communicate with. They also have bunnies, birds, lizards, and more stuff throughout the store. I also enjoy the fact that they have a Centipede for sale... Absolutely wild stuff.
Pet Valu in Vernon. Across the street from Animal City. Ehh, don't waste your time. Nice hardwood floor like in every Pet Valu, though. They have that cool Betta display but it's not plugged in, so it's not lit up nor are the Betta cups receiving air flow. It's not like the Bettas want that air flow anyway, so that's better for them. Their Betta fish did look amazing, though. One fish was extremely responsive and flared everything when I walked up to the display, we probably should have fought right there. They have the common nano tanks, supplies, food, and decorations are standard prices. Their moss balls in the Betta display were brown and dying, so that was upsetting. If you stopped by Animal City without buying anything, then the only reason you'd check this place out is because you're Betta shopping.
Pet Valu in Trumbull. The plaza that this place is in is exceptional. Fitness Edge is a 45 second walk away and you have the rest of the plaza to explore, if you were so inclined. Nice cars parked all around, okay I'm veering away from the subject. This place has nice staff, great selection of nano tanks, food, supplies, and decorations for fish. Prices are still standard, but you'd probably pay the same price on eBay or Amazon. Their Betta display was working with lights and air running. It was quite the sight to see, even if the Bettas probably didn't like their air bubble massage. The moss balls were all 100% healthy, I would buy them from here if I wanted some.
All Pets Club in Willimantic / North Windham. Directly across from the Walmart in that area. My Nexus 5 didn't have this location recognized on Google Maps, but it's literally in the plaza right across from Walmart. This place disappointed me the most, but I will be returning for a few reasons. I was disappointed because they had many empty tanks, which makes me think that the specimen in the tanks died and they haven't had any inventory to refill the tanks. Or perhaps they sell so many fish, the tanks are empty, I don't know. I was sad to see quite a few dead fish, too. I saw... I saw... a dead Blood Parrot and Botia in one tank. I was devastated, that Blood Parrot was like the size of my fist. But this place wasn't ALL bad! They had the most unique choice of fish tanks and stands out of any place in CT. Their stock of fish food, supplies, and decorations is also pretty organized and plentiful. They have all the odd pieces that you'd assume you could only get online. And their rocks and driftwood are very fairly priced, no doubt about it, the most fair prices in CT. Anyway, every All Pets Club store allows you to buy a $50 annual membership that can net you (c wat i did) savings on practically everything in the store. These savings are not BS either, you actually do save about 10% on items and livestock when making comparisons to other LFS. They have cute puppies and a bunch of other pets. Hamsters, rabbits, and more fuzzy pets. I wanted to play with the Welsh Corgi and the Boston Terriers in the back, but I had to go to Walmart. And a little praise for that Walmart across the street... I bought 20 Ghost Shrimp from them. Not only were their Ghost Shrimp $0.36, compared to Petsmart's price of $0.39, but all of them were diesel and much larger than anything I've ever encountered. Most of them were heavily berried, too! Score! And I only waited about 5 to 10 minutes until I was assisted. And get this, only two dead Mollies in the entire unit. Everything else was looking healthy and surprisingly happy. I support this store's fish selling operation because it's much better than any other Walmart. My last comment about All Pets Club is to check out their website and their other locations. From looking at their fish inventory in their Southington location, I want to say that Southington is the best place to visit, just don't go to that haunted house.
Wow, sorry about all of that LOL but I figured you might not be able to find many other people on this subreddit from CT so I did my best to describe my experiences and impressions of these stores.