I’ve kept tuberosus before.
You can transition anglers from ghost shrimp to frozen pretty easily.
Now that he’s eating live shrimp, make a feeding stick from rigid acrylic air tubing. Attach a short length of stiff fishing line.
Impale live shrimp on the line to feed your angler. You can gutload your shrimp with whatever enriched food you like.
Freeze some of the shrimp and swap them in for live ones after he associates the stick with food. He might give you a nasty look the first few times you trick him.
After he consistently takes frozen shrimp, you can swap in small pieces of cut up gel cubes or store bought shrimp.
Be careful of supermarket shrimp though. Sometimes they have a lot of added phosphate which can be bad for your fish. Got a bad batch of shrimp that did in a star and stripes puffer once. Found out later that the shrimp had a really soapy chemical taste.