I'm sorry to hear your gecko isn't doing well. Since he hasn't been eating, he is probably dehydrated. Dehydration can cause in-coordination. I'll give you a first aid measure to try. Buy some unflavored Pedialyte (yes, the kind for human infants). Prepare a shallow bath consisting of 1/2 water and 1/2 Pedialyte. Soak your gecko for about 20 to 30 minutes twice a day. Reptiles can absorb the electrolytes and fluids through their vents (where droppings pass out), so make the water deep enough to cover the vent. Be sure to supervise closely.
If the soak perks him up, you can try feeding. Get some plain chicken baby food. drop a small dollop right on the end of his snout. Most of the time, they will lick it off.
Make sure temperatures are right in his enclosure (82*F to 88*F day and night).
If these measures don't help within a couple of hours, it's time to take Mo to a reptile vet. He may be suffering from impaction (especially likely if there is sand, crushed walnut, or another loose substrate in his cage). Or, he may have an infection, an injury, or other medical condition requiring treatment. This link will take you to a directory of reptile vets:http://www.anapsid.org/vets/index.html#vetlist
If you have more questions, let me know by clicking on REPLY. I hope Mo will reach a full recovery.
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