Never believe pet store people. The only word they really understand is, "Yes".
As long as you keep buying anything, it is OK by them.
Yeah, I learned that quickly with the retail/big box pet store employees fairly quick. Found a local mom/pop type fish place in town thinking they would be more knowledgable and helpful, that doesn't seem to be the case.
When I first went in there I asked what would be good to put in a little 10 gallon with a single betta in it, the gentlemen was knew enough to recommend some more gentle types of fish that wouldn't nip at the betta.
My wife decided she really liked the rasboras we chose, so I asked the guy how big they got, and if they would be able to be kept in a smaller group (3-5)...he of course said it didn't matter how many we kept and they won't get much bigger than an inch large so they would be ok with our little tank.
From now on we're going to go look for what we like, then come home and do our own research instead of bothering with fish store employees.
On a separate note, the 5th (final) rasbora is showing signs of dying now, swam upside down for a minute not too long ago, also swimming at the very surface of the tank.
ammonia is still present (between this first and second color)
nitrites are still 0
nitrates are going back up?? was ~40-60 before I changed the water again today.