When you say you take him out to walk, what does that mean?
In one of the posts above you say he has chronic kidney disease. How do you know this? What have you been doing to make things easier on his damaged kidneys? If his kidneys are not working, he can not pee.
I am also concerned that he may be peeing in the soak and you are not seeing it. 4 hours of soaking is a long time. Normally it wouldn't hurt, but while we are trying to solve the mystery of what is going on, it would be better to only soak for a half hour to an hour. Are you watching that the water is warm ALL the time he is in the water? If it cools down only a few degrees it can affect his ability to pee and poop, digest food, move around, and much more. When a tortoise gets cold it slows down. The impact of getting chilled at this time of year is twice as strong because tortoises in the wild would be brumating right now, would be asleep until it warms up in the Springtime.
Idea:
I would try an experiment, completely covering the floor of his enclosure with paper for several days. If he pees while you are asleep or away, the paper will show it.
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Do you keep him in a CLOSED chamber? Until we figure out what is going on with his health, he needs the warmth and humidity That means a top on the enclosure that has NO vents or holes.. A top that seals to the sides of the enclosure tightly enough that zero amounts of heat and humidity can escape is needed. It is very important that the humidity and heat be contained and you cannot contain them if the top isn't sealed tightly. Small openings around lights or other things will act as a chimney and suck the heat and humidity out, so they MUST be sealed. Increasing heat should not affect the humidity that drastically.if i increase temperature - humidity will drop to 32-30.
Why do you force-feed these items? That is very dangerous and should be done ONLY as a "last resort". It is easy for liquid to go into his lungs. Very bad. When someone here says "try mineral oil", they mean put the mineral oil on a leaf and roll it up so that when your tortoise eats the leaf he also eats the mineral oil. And force feeding the water is not necessary at all. Between soaking and having a water dish easily accessible in the enclosure at all times, he should take in water on his own. While soaking they absorb water through skin and cloaca, too., besides drinking If you say he doesn't drink, what it means is that you aren't SEEING him drink. If he has clean water available in his enclosure whenever he wants it, he will drink - and, again, also they get hydrated while soaking. Stop the syringe force feeding. You could kill your tortoise doing that.I give him it by syringe (without needle) to his mouth. Also i give him drink the same way.
How much cucumber each time - one slice like a coin, or whole cucumber, or some other amount? And how much of that did he swallow?It can be one cucumber twice a week.
In one of the posts above you say he has chronic kidney disease. How do you know this? What have you been doing to make things easier on his damaged kidneys? If his kidneys are not working, he can not pee.
I am also concerned that he may be peeing in the soak and you are not seeing it. 4 hours of soaking is a long time. Normally it wouldn't hurt, but while we are trying to solve the mystery of what is going on, it would be better to only soak for a half hour to an hour. Are you watching that the water is warm ALL the time he is in the water? If it cools down only a few degrees it can affect his ability to pee and poop, digest food, move around, and much more. When a tortoise gets cold it slows down. The impact of getting chilled at this time of year is twice as strong because tortoises in the wild would be brumating right now, would be asleep until it warms up in the Springtime.
Idea:
I would try an experiment, completely covering the floor of his enclosure with paper for several days. If he pees while you are asleep or away, the paper will show it.
.
.