Frogs
It drinks through its skin rather than its mouth, which is why humidity matters more than a water bowl. Almost all of them start as tadpoles and rebuild.
Overview
Frog covers thousands of species and the ones kept as pets have almost nothing in common beyond skin. A White's tree frog, a pacman frog and a dart frog want different enclosures, different humidity and different food, and the only safe generalisation is that a frog absorbs water and everything dissolved in it through its skin.
That is why water quality matters as much for a frog as for a fish, and why hands are rinsed clean of soap and residue before touching one.
Temperament
Mostly still, mostly nocturnal, and not animals that want handling. A frog is a display animal, and the enjoyment is in watching a small ecosystem work rather than in interaction.
Dart frogs are the exception in one respect: they are diurnal, ground dwelling and active in daylight, so a planted vivarium of them is busy when the room is. They are also bold in a way that comes from having been unpalatable for millions of years.
Care and grooming
Live insects, sized to the frog, dusted for the species that need it. Nothing dried and nothing that has stopped moving, because most frogs will not recognise it as food.
The toxin question comes up constantly and the answer is settled. Dart frogs sequester alkaloids from wild prey, particularly ants, and a captive frog fed ordinary insects loses its toxicity. Captive bred dart frogs are not poisonous, which is why they can be kept at all.
Living and exercise
Ten to twenty nine gallons by species, with the balance of water and land set by the frog: fully aquatic for some, a damp planted floor for others, height and broad leaves for the tree frogs.
Low level UVB benefits several species and is not needed by all. Humidity at 60 to 80 percent with real ventilation, because a sealed wet box grows the bacteria and fungi that cause most amphibian skin disease.
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