When I went to Newport with friends on a Saturday afternoon I learned that there was an aquarium and that they have penguins. I might not be the typical aquarium visitor, but I was positively surprised about what this place had to offer. I'm not an aquarium lover, the only reason I went were the penguins. And since I went late in the afternoon I didn't have any lines! I was hoping they would have a discount after a certain hour, but that was not the case. Still, I didn't regret paying $23 for what they had to offer.
The exhibitions are very appealing, a lot of them are interactive and they have quite a variety for an aquarium. You kind of have to walk through all the areas in order to get to the penguins, but I discovered a lot more than I thought I would. They have a shark pool where you can touch smaller shark species, I found it quite an experience, even as an adult. And the staff was very friendly.
From what I read in other reviews, you might be better off going later in the day. I went around 4pm and they're still open till 6pm. It was a Saturday afternoon and not crowded at all.