Cant keep goby alive

I have went through two gobies now in my tank.. not sure why but i cant keep them alive.. they end up going under rock and i never see them again.. First one i put in was a diamond goby and he went under rock and never came back out.. the other one was just recently and was a small watchman goby.. he lasted about a week and seemed to be doing good but i havent seen him in about 5 days now.. tank is fairly new ... could that be my issue?? i have a foxface two clowns and two chromis and they are doing great.. along with serpant star and some crabs and a pistol the pistol i added about 3 days after the watchman went missing so i dont think he is the issue..

 

my yellow watchman goby dissapears all the time. I thought he was a goner so many times only for him to show up again. You never know, they may both be still alive. Maybe there's like a bar under the rocks .

If you water params are good & they were healthy I would think they'll be ok. You don't have a mantis in there hiding do you?

 

If you don't have bodies I bet you have two gobies that are alive and well.

My yashi goes missing for days on end and then I'll see him in the moonlights or he'll pop out of the rocks during feeding.

The only other possibility is that the serpent is eating them while they sleep.

 

Could be a hungry Serpent Star

 

Great.. I guess if I get a bigger goby I wont have to worry about the issue if he is eating them .. can I lift up the rock and check without pissing the pistol off to bad

 

What sized tank and how old? The diamond gobbies need a lot of well established sand. They can starve to death relatively easily without. Not sure about the YWG, but 5 days without a sighting seems like a long time. Are you sure there is no predator?

 

Ya im pretty sure he is a goner 5 days is a long time especially when he would be out and about swimming around everyday. I did notice he was always swimming up top or around the mid section like a reg. fish instead of staying around the bottom which i thought was odd.. As far as preditors go not that im aware of.. i have a few live rocks from my buddies 280 gallon tank so unless i got some strange hitch hiker im not sure.. the serpant star fish is pretty small.. i dont see him eating a fish!?? tank is almost 2 months and its a 55g