I did not read though all this mess,but from what I did read you do not have your Nile set up right.Most people use a dirt based substrate because it hold the humidity.Humidity is very important to reptiles,and most people do not truly understand the importance of this.When you keep a monitor i a fish tank with a screen top all the heat and humidity rise out the top,now you and to the fact you are using pine shaving for a substrate,witch dose not hold humidity at all.Your monitor will dehydrate very quickly,even if you see him drinking and soaking.
This was written by Dr.Sam Sweet on the importance of humidity and monitors
A couple of recent threads on basking behavior and acclimating newly-acquired monitors have slopped over into comments on cage humidity, and it is not uncommon (especially on other fora) to hear of people soaking their animals to “rehydrate” them. It might be worth considering this as a separate issue, as there seem to be some misconceptions afoot.
Monitors can only acquire water by mouth (from food or by drinking). Unless they drink, soaking does not rehydrate them, as their skins are effectively impermeable to water. Notice that we humans, with a much thinner skin keratin layer, do not bloat from taking a bath. Raising the ambient humidity can reduce the rate of dehydration, but it cannot reverse it.
As I noted in another post, monitors lose body water in feces (not much), by evaporation from their eyes (quite a bit), and by exhaling. Air inhaled by a monitor is almost always cooler than the animal’s body temperature. Even if that inhaled air is saturated (100% rh), the temperature increase will reduce the rh of the air in the lungs, and thus body water will be extracted to bring the lungful of air to saturation at the new temperature. When that air is exhaled, the body water goes with it, either all the way out of the body or at least as far as the nasal chamber. Some desert-adapted monitors (like V. griseus) have recurved nasal passages that may help condense and trap exhaled water vapor, but this is absent in species from the wet tropics, and is never as fancy as the water traps in the noses of many desert mammals.
A monitor basking in a cage is inhaling hot, locally dry air, and losing body water each time it exhales. A monitor resting in a cooler part of the cage, especially in a mostly-enclosed burrow or box or hollow, is inhaling nearly saturated air that is at the same temperature as its body and thus it is not dehydrating as quickly. It is pretty likely that monitors are aware of differences in relative humidity at various potential hiding places within a cage.
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Now when set up in a fish tank with no humidity and low heat(screen tops all the heat rises out too)they become prone to all sorts of elements such as obesity and gout.
Here is something written by Dr.Sweet on gout
The nitrogen comes from the amino acids in proteins, and starts out as ammonia (NH3), which is highly soluble and toxic. That's quickly converted to urea (NH3 NH3) and transported in that form via the bloodstream. Urea gets converted to uric acid (urea urea, so the eqivalent of 4 ammonia molecules) in the kidneys as it is being excreted, or more usually as it arrives in the cloaca. Uric acid crystallizes, and in doing so drops out of solution, allowing the animal to reabsorb the body water needed to keep the urea solution within acceptable limits. Birds do the same thing, whereas mammals (except Dalmatian dogs) excrete urea, but have much fancier kidneys than do birds or reptiles.
When an animal is chronically dehydrated its body fluid volume is reduced, and the concentration of urea solution may become high enough to cause uric acid to form almost anyplace there is a fluid reservoir. The synovial fluid in joints is a classic spot, and creates the gout that pestered your grandma. It can also happen in the kidney tubules, where the physiology is designed to concentrate those liquid wastes. The trouble with uric acid crystals is that they are not very soluble, and also serve as a template for the spontaneous growth of more crystal, so over time the kidneys can get pretty plugged up. In severe cases there are crystal deposits everywhere -- in blood vessels, membranes, you name it. A gouty animal looks all silvery inside on necropsy.
Jason has made an important point that most keepers know (I hope), which is that a number of antibiotics and antifungals that are relatively OK for use in mammals are not OK for reptiles -- they are nephrotoxic, compromising kidney function. That's pretty much an irreversible loss, and can have the same effect as chronic dehydration.
Gout is an insidious problem. You aren't going to see it coming, and by the time an animal has visible symptoms it is pretty late to start fixing things up with the husbandry. Making sure animals have access to water *that they will drink* is probably the number one thing. Lots of monitors will drink from a tub only when it has just been cleaned and refilled -- they'll soak in their own poo water, but they won't drink it. You need to keep an eye on that, as some species are fussier than others. Number two is to provide high humidity, especially in hiding spots, as a way to reduce water loss. That's why deep substrate is good and wire tops and sides are bad
Just because he is doing fine now,doesn't mean he will be ok a few years from now.I understand you want to tame your pet,but you should look into proper monitor husbandry and learn how to set him up properly first them worry about taming.I t always fascinates me that when ever someone get a new monitor,the first question is always how do I tame him.When the first questions should be is he set up right.Many people by baby Niles Evey year and VERY FEW make to there first year and of those few that do make it,they don't make it to there second year,and when you do see the odd adult Nile it is always suffering from some sort of bad husbandry element
Greg