Goliath beetle larvae health problems?

[GoHeracross]

Hi everyone. 
      I have an L3 Goliath beetle larvae that get recently seems to have taken a major change in activity level. It appears to have slowed its eating patterns and movement considerable over the past week. It has not shown any signs of pupation and is only 25 grams currently. I’m worried for the worst. Is there any advise what to do or reason for the change?

 Thanks! 

 

[kevink]

25 grams is light, in my first attempt my grub pupated at 35 grams or so, and it did form a pupa, and a pre-beetle before expiring, but that could have

been for any number of reasons, I know other breeders have successfully reared dwarf specimens. It's probably caused by some environmental reason,

with the substrate, or what they're eating. If your grub goes topside on the substrate and starts motoring around the container, it's looking for pupation

material, otherwise, maybe it's simply slowed down eating because of temperature or other reason.  Someone here might have better advice, I've got

3 L3 grubs right now, and I have been giving them moistened koi pellets, changing the substrate every 3-4 days and rinsing the grubs off with water

each time I change the substrate. The original instructions from the seller, didn't mention half of what I've learned since then from this forum. There seems

to be quite a bit more a person might want to be aware of to be really successful raising and or breeding the species. Even my guide book just mentions

the basics.