Feeding Randall's Shrimp Goby/Tiger Shrimp

[JonnyKhan]

Hi. I just got a 29g Biocube intended for a Goby/Shrimp partnership (maybe some other fish and inverts later). It's a new tank using established sand, live rock, and some bioballs from a previous aquarium. Ammonia and Nitrite are effectively zero, and Nitrate is a bit under 10 ppm. They've been settled in for three days, and the shrimp has excavated every inch. They were a pair when I got them, and still are. Both are about 1 1/2 inches long.



I can't tell if the goby is eating! As soon as I introduce the turkey baster full of finely chopped frozen mysis and brine shrimp, he disappears into the burrow (huge burrow going under one rock and with at least three openings). He stays hidden for 20 minutes at a minimum. I have tried squirting the food as close to the mouth of the burrow as possible, but I don't want to collapse it or fill it with detritus. How can I tell if the goby and shrimp are eating any of this? Should I try some other method of delivery? I did release a bottle of red copepods at startup, but they seem to have disappeared to the filter/refugium back section.

Basically, can anyone tell me how to tell for certain that my new partners are eating, and about how much? I've read that having an open water swimming fish can make gobies less shy? Any truth to that?

Thanks.