Baby NOT EATING AT ALL

I posted last week about a loss of appetite but taking into consideration that he was shedding and the upheaval of a new home, I wasn't too concerned.

Now Finn is around 9 weeks old and finished his shedding. For the last three days all I could get him to eat is a couple of crickets and a couple of waxworms. He doesn't really drink but we've bathed him and he seems to like it.

I've double checked temps/position of lights etc, his poops don't seem out of the ordinary although today's it was smaller but that would be the lack of food. He has been a bit sleepier today but I guess that would also be lack of food.

I just mashed up some calci worms and crickets with a touch of water to make a paste, dabbed it on his nose and he had about three licks worth before settling down for a bask. Ahh eat Finn!!!!! What can I do to get his appetite back bearing in mind he seems to be in fine health otherwise?? He's not all skin and bones yet but at what point should I be concerned and take him to a vet?

And is there anything particular fattening/energising I could dab on his nose while his appetite is down just to keep him going?

Any advice much appreciated

Are you measuring his weight? If his weight is stable he is probably fine and just not hungry. If his weight is declining then he could be hiding an illness that should be checked by an experienced vet.