White Sand Bed??

^ yep

my d goby has tunneled under the 3 main rocks and made homes

 

I had the same issue, my goby has made burrows and tunnels under all the main rocks that is why is recommended to place the rock in the glass. I actually had the avalanche happen in the middle of the night it was not fun trying to piece everything together at 2am.. the sand sifting star is a very tough specie to keep alive for long in a tank, they normally live up to 6 months and then they starve to death... oh by the way if you are going to have a goby be prepared to have sand all over your rocks and corals.. nothing that cant be fixed but just as a heads up

 

I do have a fuge, a 10 gallon. But my rock sits on top on my sand and i dont want to risk an avalanche lol

 

My sleeper goby has a home under one rock and the rest of the sand in my tank will he used to use my clam as a trash dump lol but now just spreads the sand everywhere

 

It's just cyano and other algae.
Black sand is usually not as fine and can have sharp edges. It also shows every speck of detritus, tiny chips of rock, poop, etc. I had black sand in my old 38 gallon and it looked dirty within a month. I also had a Diamond goby and he was fine with it. He ate any food that went into the tank.

 

I'm right in thinking you cant have a Goby and firefish in the same tank right?

 

Fire fish took the leap of faith yesterday.... poor guy didnt make it