Killifish behavior change

[Can0Beans]

I am a first-time owner of a killifish...don't know specifically what kind (the pet store didn't know either), but when I got him, he was an irredescent yellow with red spots and dark stripes on the tail. I've had him for about a month, during which time he would spend most of his time hanging out up top and chillin' out in the open. For the past 4 days, however, he has been hiding in the plants and under rocks, never (that I saw) coming out from isolation. It even got to the point where I started hand-feeding him since he wasn't coming out for food anymore. Well, today he finally makes an appearance, swimming around and hanging out like he used to, but he looks quite different....he's much darker, with most of the irredescent yellow coloration gone. I know Killis change color, but is this hiding behavior normal? Any info would be appreciated!

[theeyrietrainer]

well i dont know THAT much about killi behaviour, but something must of happened in which he got spooked, or maybe he started to mature. do you have any pictures? maybe we could identify it for you? cause some of those descriptions can match a bunch of killies!