A Guppy is a tropical fish, and has an outer covering of fish-scales.
fur
Fur, then underneath that lies skin
Having too much iron (Fe) and/or magnesium (Mg) in your water will be detrimental to any fish including Guppies (Lebistes reticulatus). Guppies do not like very hard water either.
guppies there like rabbits and bettas are very hard to breed
Fries (the term for baby guppies), are eaten by older guppies, but guppies are eaten by fish like tuna.
Only guppies breed with guppies naturally.
What are guppies
No, guppies are fish.
Guppies do not migrate.
Guppies are guppies are guppies. Tiger just describes their colouring/markings. They are the same in temperament as any other guppy.
Guppies are compatible with Bristlenose catfish, the bristlenose being one of a few catfish that can live with guppies because of the guppies' water.
Guppies are not the only fish, that give birth. Almost every kind of fish gives birth. However, guppies are pretty easy to give birth. Other fish, such as betta fish, most tropical fish, and angelfish are rather hard to breed, because they are aggressive and will eat their own young. So, I suggest guppies if you want to breed fish.