Malmö Museum Aquarium
This is a small to medium-sized aquarium, but with a surprisingly solid collection in both size and species diversity. Before visiting, I hadn't heard much about it, apart from the fact that it's one of very few places in Europe to have kept shield-tailed agama (Xenagama taylori), which was one of my main targets.
Species-wise, the collection can be really strong, with a good mix of common and uncommon species. Over the years it has housed several species that have only been kept in a handful of public collections, making it well worth a visit if you're interested in seeing something a bit different.
When entering, I recommend turning right and starting with the Swedish/European section. This area has several smaller tanks and terrariums, plus two larger aquariums with bigger fish, one of them built around parts of a shipwreck. Here you'll find a nice selection of native freshwater and marine species.
After finishing the European area you reach the tropical zone. First there's a door on the right leading into a small jungle-themed side section with two terrariums and two mixed land-and-water exhibits. Back through the door is the main tropical section, which makes up the largest part of the aquarium. This area contains a wide range of terrariums and aquariums, plus a nocturnal room with reptiles that are active at night.
Overall, this is a really good collection and one I definitely recommend if you're visiting Sweden and happen to be in the area, especially from a species collector's perspective. On top of the aquarium, they also have a nice taxidermy collection, which makes the visit even more worthwhile.
Reptile