I tore down the 37gallon and upgraded to a 75 which has in it a niger trigger, neon dottyback, bicolor blenny, and 4stripe damsel. The tusk is in a 20g qt with a resin cave which it likes to hang out in and two med/large pieces of pvc. on the back and one side of the qt (the side of the cave) I have black paper taped so that the cave side is dark, and a small light illuminating the right side of the tank. I made sure that the bag water wasnt far off from the qt water and acclimated him accordingly. the qt has a filter, (with media from the 75g), a small piece of sacrificed LR, a maxijet agitating the surface, a heater. He comes out in the evening and moseys around the tank but so far I have not observed him eat/hunt the ghost shrimp, and hasnt looked very interested in the speared chunks of mussel octopus or shrimp I have offered from a skewer (while hiding behind the side of the tank covered with paper so he cant see me, well, as much as possible anyways)
Ok I just tested the water. Even though I had one of those seachem ammonia alert badges in there, I didnt realize the ammonia was so high (1.0). So I went ahead and just put him in the 75 gallon just now. QT is a great idea in theory but every fish I have ever tried to QT before adding to the tank I have had issues with. I have been keeping fish for years and years and if an experienced aquarist like me cant keep a fish happy in qt then using a qt is obviously doing more harm than good. All the 'experts' say just to use a sponge filter from your established tank and that is adequate supply of bacteria to filter waste but IME it never has been. I guess I will stick with obtaining healthy specimens and getting them back into the most natural setting possible. Well I hope that he adjusts to life in captivity. I did put his cave in there and its almost lights out for the night.