About a month ago, we bought a Tiger Pistol Shrimp and a Barber Pole Goby from the LFS
. They seemed to adapt to tank life rather well. Initially they created separate burrows, but within about a week they paired off nicely. The Pistol Shrimp was very industrious, digging furiously and moving lots of sand about the aquarium. The Goby seemed to like the burrows that were dug, and I could always see his face peering out from one of two spots in the aquarium. Almost two weeks ago, the Pistol Shrimp seemed to disappear, no snapping sound, no movement of sand. I could see the Goby, so I thought that maybe the shrimp was moulting. However, since then, the Goby has disappeared. I saw the Goby at evening feed on Monday, but have not seen it since. As such, I have not seen the pistol shrimp in nearly two weeks, and I have not seen the goby in 4-5 days. I am concerned. The rest of the tank is doing very well. I tested water levels yesterday, and pH was 8.2, and Ammonia, Nitrite and Nitrate were all 0.
My concern is that these two have accidentally buried/trapped themselves under the rock and sand. I continue to look for them at feeding times, but still no luck. My concern is growing with each day that I don't see either one.
At what point do I presume that they are dead? After that, should I consider getting another pair? Any advice?