All dwarf gouramies are exactly the same species -
Colisa lalia. What different LFSs call the different color morphs is entirely up to them and not standardised.
Male dwarfs are the colorful ones. Females are duller brown or silver-grey. Males are also more aggressive and territorial than their female counterparts. for this reason, your fish won't do well in a 5 gallon with other fish - especialy not with fish that spend a lot of time in the upper layers or that are prone to being bullied or nipped - as would be the case with guppies. Even if this were not the case, over-stocking would be a major issue in so small a tank.
Furthermore, dwarf gouramies are very sensitive fish and easily succumb to disease or stress-related problems. Small tanks do not offer the most stable environment. Fluctuations happen more often - eg heat loss is more rapid due to the higher surface area to volume ratio. Equaly, rises in temp. as a result of lighting are more rapid and so is the accumulation of waste, for obvious reasons. These things mean dwarf gouramies, dispite their small max. size of 2", are not suited to small tanks.
You could conceivably keep this single fish in a 5 gallon with a few shrimp (2-3) but you shouldn't add anything else. Also, if the tank isn't cycled (ie hasn't been set up with some source of ammonia for at least a month), the gourami will probably die over the next few days so I'd strongly urge you to return him to your LFS and begin a
fishless cycle (details can be found in my signature).
Just in case, could your fish actualy be a honey gourami (Colisa chuna/sota) and not a dwarf? These grow to 1.5" and are hardier but still aren't suited to life in a 5 gallon with other fish simply because you'd be over-stocked. A trio of MALE guppies would only just about fit in (and maybe a couple of shrimp) but the same mild territorial aggression issues as with the dwarf apply. You'd need to plant the tank heavily. Again, these are not suitable candidates for cycling a tank.
Here are pics of each fish:
Dwarf:
http
/www.wetwebmedia.com/Anabantoids/Honey_GouramiAQ.jpg and another:
http
/jjphoto.dk/fish_archive/aquarium/colisa_lalia.htm (furthermost left is closest to the wild coloration)
Honey:
http
/www.plantedtank.net/images/fish/honeygourami.jpg and another:
http
/jjphoto.dk/fish_archive/aquarium/tr...aster_chuna.htm (right pic is of wild-type in breeding coloration - ie the black ventral region)