Are yellow jags a bit more expensive than the black/white ones? are there any differences besides body color? does it occur in both captive-bred and wild specimens?
I never heard of a dark or yellow Jaguar Cichlid (Parachromis managuensis), I have seen a red hybrid but thats about it. Maybe you are reffering to a darker stressed fish versus a fish that is used to its tank?
"Yellow" Managuense are generally either regular morph females, female Gold Managuense, or some other fish (Loiselle or Motaguense) being called a Managuense. I have never seen a male yellow Managuense.