I have a female a. Agassizii that is only accompanied by a yellow panchax and a few ottos and is almost always a pretty yellow. Is this natural, or could she be calling out?Good thought MacZ, there was about 5 male Borellii in with them and did not think to mention it being a different species, but hormones/pheromones does sound plausible.
If the females are in a condition that is good enough to be ready to breed, they will often color up. Males or no males. They are fat and eggy and ready, and letting everyone else know it. They don't understand that no male will be swimming into their territory. They're just ready and waiting regardless. I've had all-female tanks where most-to-all were colored up and good to go many times. That the fish in that shop are all still yellow indicates that they being given good care and excellent conditions more than anything else. Whoever purchases them will be lucky indeed.Was at my LFS and they have about dozen female agassizii with no males or fry, all of them were canary yellow and still are a week later anybody else ever see this?