betta and labeo bicolor fish

Question
I have a betta male fish and i just recently added a betta female and one labeo bicolor fish to my aquarium.  when i watched to see if the betta male would get along with the labeo bicolor, i saw that the betta male kept pushing the labeo away as if he did not want the labeo in the same tank with him.  The labeo bicolor did not defend himself at all when the beta pushed him.  My question is why was the beta aggressive to the labeo bicolor?  I was told by the sales person at the store that the two fish would get along if I bought the labeo bicolor.  Are these fish not compatible?

Answer
Dark colors like black and dark blue are aggression triggers for bettas. That "pushing" you saw was fighting posture. To put it simply....get the shark out of the tank before the betta bites him up. The individual at the pet shop gave you in correct information. For that matter they should not have let you add a female to that tank either...the male will end up harassing the female to death if not pushing her to the point of stress.

Both of those fish need to come out of that tank....not only the female but the shark as well.

Remember....no dark fish in the tank with the betta....go with mollies (not black), tetras, danios, corydoras and things of that sort....but stay away from barbs.