Iv tried krill he had no interest... I fed maybe 2 days ago and he stuffed himself and tried to feed today and he maybe had 1-2 worms then stopped eatingWater params are good.
I recommend increasing feedings. Might be weak from underfeeding. An earthworm or two will help beef him up. My schoutedeni also eats krill. I have a small tank where I farm snails as well...
If still acting weird, may have some disease that other experts on here may be able to help you with.
Continue to observe, good luck!