Young Horsfield Inactivity

Claire Waldron

New Member
Joined
Sep 29, 2025
Messages
7
Location (City and/or State)
Powys, Wales
We have a 2 year-old Horsfield tortoise named Koopa. She lives indoors in a well-sized tortoise table. The basking area of her enclosure is 35°C, and the cool end is 20°C. She has access to hides, and a shaded segment at the end of her enclosure which is a little colder and darker than the rest. We normally bathe her twice a week.

When we initially got her around one and a half years ago she was very active, however over the last month or two she has become very inactive - generally remaining burrowed for very long periods of time, and very rarely coming up to eat independently. She has also lost some weight (at the end of July she was weighing 75g, and today she weighs 67g), likely due to the lack of eating. When we get her out to bathe her, she will become active after a few minutes, and will happily walk around and explore. She shows no signs of illness - her eyes are bright and clear, her shell appears healthy, there's no nasal discharge, and so on. However, when we put her back in her enclosure she almost immediately goes and burrows!

We don't really know what's causing this, if it's dangerous, or how to prevent it. Any help would be much appreciated! :)
 

_The_Beast_

Well-Known Member
Joined
Oct 3, 2021
Messages
373
Location (City and/or State)
Canada
How's the lighting situation? Is she in a closed or open enclosure?

It could be that with the seasons changing she's winding down for winter. If you aren't brumating, then adding additional lighting + ensuring stable temps can help. What UV source are you using and when was it last replaced (assuming tortoise is indoors)?
 

Claire Waldron

New Member
Joined
Sep 29, 2025
Messages
7
Location (City and/or State)
Powys, Wales
How's the lighting situation? Is she in a closed or open enclosure?

It could be that with the seasons changing she's winding down for winter. If you aren't brumating, then adding additional lighting + ensuring stable temps can help. What UV source are you using and when was it last replaced (assuming tortoise is indoors)?
It is an open topped enclosure with a 125W combination UVA and UVB bulb which has only been used for 2 months. The room she's in has all day light through a window :)
 

Littleredfootbigredheart

Well-Known Member
Joined
Dec 28, 2023
Messages
7,679
Location (City and/or State)
UK
We have a 2 year-old Horsfield tortoise named Koopa. She lives indoors in a well-sized tortoise table. The basking area of her enclosure is 35°C, and the cool end is 20°C. She has access to hides, and a shaded segment at the end of her enclosure which is a little colder and darker than the rest. We normally bathe her twice a week.

When we initially got her around one and a half years ago she was very active, however over the last month or two she has become very inactive - generally remaining burrowed for very long periods of time, and very rarely coming up to eat independently. She has also lost some weight (at the end of July she was weighing 75g, and today she weighs 67g), likely due to the lack of eating. When we get her out to bathe her, she will become active after a few minutes, and will happily walk around and explore. She shows no signs of illness - her eyes are bright and clear, her shell appears healthy, there's no nasal discharge, and so on. However, when we put her back in her enclosure she almost immediately goes and burrows!

We don't really know what's causing this, if it's dangerous, or how to prevent it. Any help would be much appreciated! :)
Hello! What you’re describing sounds typical of a winter slow down, a lot of tortoises do this this time of year, if you aren’t going to brumate her, you need to boost her ambient temperature, so the cooler end is more in the 23c range, and increase lighting by a few hours, essentially tricking her into thinking it’s a warmer longer summer day.
To boost ambient heat you can use a ceramic heat emitter, it’s a none light emitting heat bulb to boost ambient heat/provide night heat, it runs on a thermostat.

It’s virtually impossible to keep your ground temperature where needed with an open top in our cold uk weather, I’ll go more into that in a second.

It is an open topped enclosure with a 125W combination UVA and UVB bulb which has only been used for 2 months. The room she's in has all day light through a window :)
I would definitely suggest upgrading your lightning situation. I’d definitely get some ambient lighting in there, that will affect activity levels.
It’s best going with a separate uvb and heat set up(still mounted by each other), having combined heat and uv, means when adjusting your height to create the desired basking temperature, you’re messing with your UVI zone, they are much more desiccating on the shell and their uv output often very unreliable.
There’s the added fact of uv timing, with the uv timing, every other source of information will tell you 12hours of uv. This is essentially an old fashioned rule that has stuck with a lot of keepers, it stems from the presumption that once the basking light or ambient lighting is on, ie the ‘sun’, that uv must coexist the same amount of hours. Fact is, uv rays only peak for a few hours a day, anyone with a uv meter will confirm this. No tortoise is blasted with 12 hours of uv in the wild, therefore it’s not necessary in captivity. Whilst not necessarily dangerous, it’s potentially annoying to the tortoise to have 12hours on uv in the enclosure.
The right uv bulbs are much more expensive to replace once their uv strength diminishes, so it’s definitely best having it on a 4 hour timer that provides them with all the uv they need, saving your bulb life.
Then some cheaper led lighting for your ambient 12 hour light cycle as well as the basking light on the same 12hrs, your ceramics(if needed in colder weather) will run 24/7 on a thermostat, hopefully that will all make more sense once you read the links, take all the time you need🙂
The most recommended up to date indoor uv option is t5 tube fluorescent bulbs, they disperse the uv light over a much wider area. Recommended brands are Arcadia proT5 kit 12% or zoo med reptisun t5 10.0(hood usually sold separate)

I think you’ll find these links useful to go over, she’s at the age where a closed chamber shouldn’t be as important, but if she’s been raised in an open top, I’d suggest a closed set up for a bit longer/during winter.

This thread covers correct equipment(uvb, heating bulbs, lighting etc), correct levels, importance of a closed chamber for younger tortoises(only way to maintain the humidity you need, I know I say 80+ for babies, as yours is slightly older, it’ll be ok if it’s lower at times), appropriately maintaining the humidity, safe substrates, there’s lots of visual examples for everything, and a really handy diet link to check out! If going with a greenhouse, the lower the ceiling height, whilst still allowing for recommended bulb height, the better! But I’ll add some more ideas below for closed chambers, I think a bunch of the cover options will hopefully work for the set up you have

This includes different closed chamber options, like I say, she might not need it long term, but it’ll definitely come in during winter. Some of the covers in here can be cheaper to make, but I will say the most efficient closed set ups are melamine/pvc vivs. A place called Southdown aquatics actually does custom sized vivs in the uk

This includes lots of inspiration for an adult set up both indoors and out! The indoor bit has some good ideas to tackle indoor space whilst still providing the needed roaming room! Check comments too, I’m always adding to it, I have a huge back log I need to add. I know the recommended adult size is intimidating to some, especially if you’ve been lead into thinking ahe’ll be fine in a smaller set up(very common) but tortoises long term health really does rely on lots of roaming room. If you’re unable to go that big, go as big as you can. I’m not saying it’s priority right now, but sizing can definitely affect activity and she will be reaching the age of needing an adult size in the foreseeable future.

Lastly, this one here is probably most important to go over and keep on hand, it’ll help you avoid the wrong bulbs, substrates, housing etc, I always encourage double checking purchases on the forum too before buying😊

Phew! Really hope this all helps! I know it’s a lot to go over sorry😣but take all the time you need! They’ll always be folks to help with any further questions! We can break things down bit by bit and help improve the current enclosure step by step, priority is going to be temperatures and lighting to hopefully perk your little one up, welcome to the forum🐢💚
 

_The_Beast_

Well-Known Member
Joined
Oct 3, 2021
Messages
373
Location (City and/or State)
Canada
It is an open topped enclosure with a 125W combination UVA and UVB bulb which has only been used for 2 months. The room she's in has all day light through a window :)
The UV a tortoise needs to grow is blocked through by glass and the days are getting shorter, which means less ambient light as well. To keep your tort awake through the winter you need improved lighting (go UV tube, separate flood light for basking, and LED for increased ambient light) and keep the temps up. The post by @Littleredfootbigredheart above has tons of info on how to do that.

Unless you want to brumate your tort, in which case the are other resources folks can share for how to do that safely.
 

Tom

The Dog Trainer
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68,511
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@_The_Beast_ spelled this out perfectly and @Littleredfootbigredheart gave an in-depth answer with lots of good info.

Your problem is that you are using the wrong lighting, and your temperatures are too cold. The mercury vapor bulbs shouldn't be used at all, for a variety of reasons, but the whole enclosure needs to be heated and well lit, not just one area under one bulb.

Here is a breakdown of the four heating and lighting essentials:
  1. Basking bulb. I use 65 watt incandescent floods from the hardware store. Some people will need bigger, or smaller wattage bulbs. Let your thermometer be your guide. I run them on a timer for about 12 hours and adjust the height to get the correct basking temp under them. I also like to use a flat rock of some sort directly under the bulb. You need to check the temp with a thermometer directly under the bulb and get it to around 95-100F (36-37C).
  2. Ambient heat maintenance. I use ceramic heating elements or radiant heat panels set on thermostats to maintain ambient above 80 degrees day and night for tropical species. In most cases you'd only need day heat for a temperate species like Testudo or DT, as long as your house stays above 60F (15-16C) at night. Some people in colder climates or with larger enclosures will need multiple CHEs or RHPs to spread out enough heat.
  3. Ambient light. I use LEDs for this purpose. Something in the 5000-6500K color range will look the best. Most bulbs at the store are in the 2500K range and they look yellowish. Strip or screw-in LED bulb types are both fine.
  4. UV. If you can get your tortoise outside for an hour 2 or 3 times a week, you won't need indoor UV. In colder climates, get one of the newer HO type fluorescent tubes. Which type will depend on mounting height. 5.0 bulbs make almost no UV. I like the 12% HO bulbs from Arcadia. You need a meter to check this: https://www.solarmeter.com/model65.html A good UV bulb only needs to run for 2-3 hours mid day. You need the basking bulb and the ambient lighting to be on at least 12 hours a day.
More info here:

This is a brumation thread. You are firmly in the "limbo" territory described in the thread. It needs to be warmer and brighter in your enclosure ASAP:

All of your questions are welcome.
 

Claire Waldron

New Member
Joined
Sep 29, 2025
Messages
7
Location (City and/or State)
Powys, Wales
It is an open topped enclosure with a 125W combination UVA and UVB bulb which has only been used for 2 months. The room she's in has all day light through a window :)

Hello! What you’re describing sounds typical of a winter slow down, a lot of tortoises do this this time of year, if you aren’t going to brumate her, you need to boost her ambient temperature, so the cooler end is more in the 23c range, and increase lighting by a few hours, essentially tricking her into thinking it’s a warmer longer summer day.
To boost ambient heat you can use a ceramic heat emitter, it’s a none light emitting heat bulb to boost ambient heat/provide night heat, it runs on a thermostat.

It’s virtually impossible to keep your ground temperature where needed with an open top in our cold uk weather, I’ll go more into that in a second.


I would definitely suggest upgrading your lightning situation. I’d definitely get some ambient lighting in there, that will affect activity levels.
It’s best going with a separate uvb and heat set up(still mounted by each other), having combined heat and uv, means when adjusting your height to create the desired basking temperature, you’re messing with your UVI zone, they are much more desiccating on the shell and their uv output often very unreliable.
There’s the added fact of uv timing, with the uv timing, every other source of information will tell you 12hours of uv. This is essentially an old fashioned rule that has stuck with a lot of keepers, it stems from the presumption that once the basking light or ambient lighting is on, ie the ‘sun’, that uv must coexist the same amount of hours. Fact is, uv rays only peak for a few hours a day, anyone with a uv meter will confirm this. No tortoise is blasted with 12 hours of uv in the wild, therefore it’s not necessary in captivity. Whilst not necessarily dangerous, it’s potentially annoying to the tortoise to have 12hours on uv in the enclosure.
The right uv bulbs are much more expensive to replace once their uv strength diminishes, so it’s definitely best having it on a 4 hour timer that provides them with all the uv they need, saving your bulb life.
Then some cheaper led lighting for your ambient 12 hour light cycle as well as the basking light on the same 12hrs, your ceramics(if needed in colder weather) will run 24/7 on a thermostat, hopefully that will all make more sense once you read the links, take all the time you need🙂
The most recommended up to date indoor uv option is t5 tube fluorescent bulbs, they disperse the uv light over a much wider area. Recommended brands are Arcadia proT5 kit 12% or zoo med reptisun t5 10.0(hood usually sold separate)

I think you’ll find these links useful to go over, she’s at the age where a closed chamber shouldn’t be as important, but if she’s been raised in an open top, I’d suggest a closed set up for a bit longer/during winter.

This thread covers correct equipment(uvb, heating bulbs, lighting etc), correct levels, importance of a closed chamber for younger tortoises(only way to maintain the humidity you need, I know I say 80+ for babies, as yours is slightly older, it’ll be ok if it’s lower at times), appropriately maintaining the humidity, safe substrates, there’s lots of visual examples for everything, and a really handy diet link to check out! If going with a greenhouse, the lower the ceiling height, whilst still allowing for recommended bulb height, the better! But I’ll add some more ideas below for closed chambers, I think a bunch of the cover options will hopefully work for the set up you have

This includes different closed chamber options, like I say, she might not need it long term, but it’ll definitely come in during winter. Some of the covers in here can be cheaper to make, but I will say the most efficient closed set ups are melamine/pvc vivs. A place called Southdown aquatics actually does custom sized vivs in the uk

This includes lots of inspiration for an adult set up both indoors and out! The indoor bit has some good ideas to tackle indoor space whilst still providing the needed roaming room! Check comments too, I’m always adding to it, I have a huge back log I need to add. I know the recommended adult size is intimidating to some, especially if you’ve been lead into thinking ahe’ll be fine in a smaller set up(very common) but tortoises long term health really does rely on lots of roaming room. If you’re unable to go that big, go as big as you can. I’m not saying it’s priority right now, but sizing can definitely affect activity and she will be reaching the age of needing an adult size in the foreseeable future.

Lastly, this one here is probably most important to go over and keep on hand, it’ll help you avoid the wrong bulbs, substrates, housing etc, I always encourage double checking purchases on the forum too before buying😊

Phew! Really hope this all helps! I know it’s a lot to go over sorry😣but take all the time you need! They’ll always be folks to help with any further questions! We can break things down bit by bit and help improve the current enclosure step by step, priority is going to be temperatures and lighting to hopefully perk your little one up, welcome to the forum🐢💚
Thank you so much :) There's so much helpful advice there and I'll definitely check out those linked threads! Thanks again :)
 

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