There could be appetite supreesion . In addition they could feel out of their natural environment . I feel your pain . I had bangaii cardinals that refused everything until I tried live guppies . After months of eating only that did they try frozen . Before them I had frog fish that only ate live . They literally starved to death even though I tried almost everything .that was before I found the saltwater tolerant strain of guppy . When you are feeding live brine shrimp is it newly hatched ?
Thanks flfireman I will purchase NLS powder