Bad shark

Question
I have a reasonable sized tank with good cover, but my rainbow shark keeps attacking my female fancy guppy. Now it is clear to me that the man at the pet store lied when he said they would get along, but why did it only attack my female?? And do you think sword tails would get along with my rainbow shark?

Answer
Hi Drew,

Really bad news.  Petstores do not tell customers the dangers of red tailed and rainbow sharks.  They are extremely aggressive fish.  This is a completely normal behavior for it.

I'd consider getting the thing a new home.  I no longer keep them. Too many times they killed my fsih.

Happy fish-keeping.