Local pet store often mislabel or make up names for fish in hopes of making them more marketable. If you can post a photo of it, or give as detailed description as possible, perhaps the collective minds here can help identify it's true name so you can study more about it.
Hummingbird Tetra: Characidium fasciatum a.k.a. Peru Darter Tetra, Walking Tetra
Size: 3" max pH: 5.5 - 7.5 dH: 2 - 25 Temp: 64 - 81F, Origin: Clear streams in South America from the Rio de la Plata
" This unusual little guy is something you just don't see often. Nope, it's not a common Chinese algae eater, although it may look like one, it's actually a Hummingbird Tetra! A peaceful loner that should be kept either singly, or in a large group of eight or more fish. If kept in groups smaller than about eight, fish can act aggressively. Combine with small to medium-sized fish of upper swimming levels. An inquisitive fish, always investigating the tank floor. Yes, these will nibble on algae!!! Breeding the Hummingbird is fairly easy. A pair spawns on the bottom, laying side to side. The parents should be removed from the tank after the eggs are laid. The 150 eggs fall between rocks and hatch after 30 to 40 hours. The fry have very small mouths and should be raised on food tablets, infusoria, and Artemia. A robust species, that is suitable for most community tanks! "
got some in my 120 and love them. not the most colorful fish out there, but very fun to watch. they dont bother other fish or even adult shrimp (i have tons of wild for cherries breeding like rabbits). mine are avid hunters of scuds and probably baby shrimp that infest my hc and hairgrass forground. they kind of remind me of those snow foxes hunting for voles in the snow, they sit on the plants and stare into them looking for the food. they can sit for minutes at a time very still then suddenly dive into the hc or grass to nab a scud/shrimplet.... they are pretty cheap as they are not colorful, so buy a bunch if you can house them.
PS, mine look like the link and not the pic from AZ. i have no idea what that is pictured, but they are known for mislabeling things.