Story of the firefish

so I had to red firefish that I added a couple of months ago he is he was doing fine until this Friday,when I added a purple firefish and then by Sunday at the red firefish disappeared,  it came out briefly Sunday evening to eat and then hid again, what should I do should I take the red firefish out or should I wait and things will calm down by itself.  And also since Sunday the yellow  watchman goby has disappeared too. Got some bad advice from LFS staff saying that they both will be fine. from what i read online I made a big mistake, I tried taking them out but cant catch em unless I take all the rocks out. The Water parameters are fine with the nitrate reading at zero, So i think they are not dead yet.

How are the fish doing?
Most of us have made that mistake of making an impulse purchase in this hobby. Some times it's a coral or fish or clam or what ever it is that caught our eye. I always recommend doing research on any fish you look to add into your set up. While it is easy to talk to someone that works at a LFS you have to take their advice with a grain of salt. They are looking to make a sale so they might bend the truth or flat out lie to make a sale. Mostly everyone has a smart phone so a quick google search is always a good idea

Well, the red firefish is in hiding, i have only seen it every now and then, in the past couple of days. but mostly it is hiding. and There is no sign of the Yellow Watchman Goby.

Someone was telling me to add another firefish to have odd numbers, and the one hiding should come out. ??