Xenia won't eat anything so do'n worry about that one.
Torch will sometimes benefit from small meaty foods like Mysis Shrimp.
I don't know what a Foxspawn is.
Open brain is the only one that you should probably feed on a regular basis. Mysis Shrimp, minced silverside, scallop, etc. It will eat any meaty food you give it. The feeding tentacles will come out at night but it can be trained to feed in the light if you're consistent.