Help suspected dead diamond goby
 

Hi I added a diamond watchman goby 23 days ago in my 54 gallon corner tank. He was drip acclimated and I have never seen him since he was added to the tank is it possible he burrowed and just died under the sand somewhere? He has no aggressive tank mates and my readings for Ammonia and Nitrite have been 0 consistently and my nitrate is usually in range from 0-10PPM I tested today and my nitrate is around 40 Ppm so i did a 10% water change and tested a few hours later and nitrates are at 40 PPm. Should I go looking for the suspected dead diamond goby? I have 77 pounds of live rock in this tank and 80 pounds of livesand, and would it be better to let the clean up crew maybe get him or go searching for a body which would cause stress to the other inhabitants plus the risk of crushing one of the cleaner shrimps in my tank and smaller fish or should I get some type of nitrate removing media or bottled fluid to help reduce the nitrates? Any feedback would be great thank you.

If it was under a couple of inches I wouldn't go looking for it. I just let my tank ride. Maybe a water change or two.

He was about 4 inches pretty big guy

Update: I changed 10 gallons of water in my 54 gallon tank and replaced filter media and tested again after an hour and it's still at 40 ppm for Nitrates