Single Male Golden Wonder Killifish...could He Be Nipping Tails?

[blur411]

I just got a Golden Wonder Killifish, I have a 55 gallon tank with some Male Guppies, loaches, platties and mollys, medium planted. Anyways, I noticed today (4 days after buying him), that one of the yellow guppies has some areas on his tail that are nipped. Did he do it? Also, I read on here someone said a single male is the best option (what I have) but LFS said I should get him friends...any idea on what is best?

 

[N0body Of The Goat]

At some point, that new killifish will try and eat those Guppies, no doubt about it in my mind. They are opportunistic predators with gaping mouths, not to be trusted at all with streamlined fish that stay under ~7cm excluding their tail (when the killifish is approaching full size).

 

[blur411]

damnit for the LFS telling me it was a community fish and OK with what I have... So, I guess I will try and return it!