Critters like frogs and lizards require much more specialized tanks and foods depending on the species. A freshwater aquarium is more simple overall. Again, it depends on specifically the species of fish as well.
A fish aquarium will require water, and depending on how big your aquarium is, it will be pretty heavy. When you go away for vacation, you won't be able to move it to the pet sitter. A critter aquarium won't provide enough ventilation so you must change bedding often for your critter. The critter will be more mobile for vacations.
Most critter aquariums weren't made to hold water so you can't switch them to a fish aquarium in the future. Fish aquariums were made to hold water so you can use them as either a fish or a critter aquarium. Both critter and fish aquariums are basically the same. You'll have to feed the animals at least once a day.
fish are a lot easier to care for because you just have to feed them and make sure the water temperature is ok. a critter aquarium you need to buy whatever they need like there habitat and you also need food and they need to have there's to a good temperature also
Pro's of a fish tank include beautiful fish most of the time, and then an ugly messy clean-up of filter and bottom. Critters are fun, harder to leave alone.