Yellow watchman goby turning yellow

[ShadowWolfBloodMoonBorn]

I bought 2 yellow watchman gobies one yellow one gray. They were in the same tank but I bought them different days so I had to buy a pistol shrimp for both. I never saw my pistol shrimp eat and when I tried to put the food in the burrow it would just push it out. Anyways I don’t know if this has anything to do with it but I haven’t seen ether shrimp in recent vacuuming so I’m assuming they are dead. Anyways both WM shared a tunnel but now my gray is turning yellow and has moved to the other end of the tank. It’s a nano tank though, 30gal, so they could just have one tunnel that runs along the back to both sides. Any clue why my gray is now yellow? Also I had a few feather dusters that eventually abandoned their tubes months ago and I never saw them pop back up so I relinquished to the thought they had died but now I have a new tube. So how long can they stay hidden before popping up again?

 

[BlenniesAndTangs]

Its happend to a lot others before, and I believe they used to be sick, or their just maturing!

 

[Tired]

IIRC the color is a sign of sexual dimorphism, but watchman gobies can change sex.

 

[ThRoewer]

Color changes with fish can have many reasons and are quite common. With gobies it is often an adaptation to their environment, i.e. camouflage, especially with shrimp gobies that didn't live with a shrimp for a while.
As for pistol shrimp not taking food: they usually find enough. They may also eat the poop of the gobies. And finally, they act as cleaner shrimp for the gobies and pick them clean of all parasites that may be on their skin and in their gills.

 

[ShadowWolfBloodMoonBorn]

Thank you I was hoping it wasn’t turning male. But I guess, correct me if I’m wrong, if they were sharing a burrow they probably wouldn’t be both male. Is it best to have them paired with a shrimp?

 

[Tired]

They don't need a shrimp, but they probably appreciate the shrimp digging them an extensive house to live in, and it definitely shows off some cool behaviors. I'd certainly pick up a tiger pistol shrimp, if I were you.