Keeping Aphonopelma moist

[A guy]

Before I start, I want to preface this by saying that I'm not claiming anything, I simply want to share what I've experienced

So this started when I received my Aphonopelma mooreae group, about 3 years ago or so. They were directly from Dr. Jorge Mendoza's captive breeding project in Mexico. Each one of them were guaranteed to be "fresh bloods" for the hobby. In exchange, I gave him one of my kidneys, jk

I originally received 4 specimens. They were all about 1.5" or so. Some were bigger than others, small juveniles, I would say.

I've always kept Aphonopelma species in the typical dry substrate set up but for some reason I wanted to experiment with these guys(I know, not the best species to be experimenting on).

From the start, I gave them husbandry that was almost Theraphosa like. Moist substrate and containers with tons of cross ventilation to avoid stagnant air. Not as moist as Theraphosa but I never allowed their substrate to fully dry out. Their temps were seasonal, gets to the high 60s during winter and high 70s in the summer.

With this set up, I've never experienced food rejection from any of them unless they are in premolt. Also, their growth rates were extremely fast. Not just for Aphonopelma but just overall. They were even outgrowing some of my Asian fossorial species and Pamphobeteus species. Citharognathus tongmianensis and Pamphobeteus sp. solaris to name a few.
I would regularly get molts from them every 3 months.

When I sexed them out 1.3 - I simply stopped keeping the male's substrate moist but everything else was similar. He still never rejected food and was still a great eater but his molting now had large intervals between them. The females on the other hand were still kept moist and were basically outgrowing almost every species that I had. Now, after 3 years, the females are still kept on moist substrate but now I do let it dry out for a little. The females still molt out regularly and in 3 years, they are now 3.5" and have matured.

Fast forward to February 2024, I've acquired another female mooreae 2.25" , she was the same size as my male at that time. Kept her the same as my others and the results were very consistent.

Also, at the end of 2023 I've received a female Aphonopelma bicoloratum sub adult from a friend and a small sling from another. I kept them in similar husandry with my mooreae and my female bicoloratum is molting regularly with 3 molts in 2024 and now just molted again in 2025. The smaller bicoloratum, I'm experiencing the same results, very constant molts but smaller growth with every molt compared to the mooreae.

Current photos, although the size difference from the pictures aren't showing very accurately, you will still see the very obvious difference.

1.1 Aphonopelma mooreae

From the same import of 2022


1.1 Aphonopelma mooreae

Same male from 2022, female from 2024

 

[Mustafa67]

Before I start, I want to preface this by saying that I'm not claiming anything, I simply want to share what I've experienced

So this started when I received my Aphonopelma mooreae group, about 3 years ago or so. They were directly from Dr. Jorge Mendoza's captive breeding project in Mexico. Each one of them were guaranteed to be "fresh bloods" for the hobby. In exchange, I gave him one of my kidneys, jk

I originally received 4 specimens. They were all about 1.5" or so. Some were bigger than others, small juveniles, I would say.

I've always kept Aphonopelma species in the typical dry substrate set up but for some reason I wanted to experiment with these guys(I know, not the best species to be experimenting on).

From the start, I gave them husbandry that was almost Theraphosa like. Moist substrate and containers with tons of cross ventilation to avoid stagnant air. Not as moist as Theraphosa but I never allowed their substrate to fully dry out. Their temps were seasonal, gets to the high 60s during winter and high 70s in the summer.

With this set up, I've never experienced food rejection from any of them unless they are in premolt. Also, their growth rates were extremely fast. Not just for Aphonopelma but just overall. They were even outgrowing some of my Asian fossorial species and Pamphobeteus species. Citharognathus tongmianensis and Pamphobeteus sp. solaris to name a few.
I would regularly get molts from them every 3 months.

When I sexed them out 1.3 - I simply stopped keeping the male's substrate moist but everything else was similar. He still never rejected food and was still a great eater but his molting now had large intervals between them. The females on the other hand were still kept moist and were basically outgrowing almost every species that I had. Now, after 3 years, the females are still kept on moist substrate but now I do let it dry out for a little. The females still molt out regularly and in 3 years, they are now 3.5" and have matured.

Fast forward to February 2024, I've acquired another female mooreae 2.25" , she was the same size as my male at that time. Kept her the same as my others and the results were very consistent.

Also, at the end of 2023 I've received a female Aphonopelma bicoloratum sub adult from a friend and a small sling from another. I kept them in similar husandry with my mooreae and my female bicoloratum is molting regularly with 3 molts in 2024 and now just molted again in 2025. The smaller bicoloratum, I'm experiencing the same results, very constant molts but smaller growth with every molt compared to the mooreae.

Current photos, although the size difference from the pictures aren't showing very accurately, you will still see the very obvious difference.

1.1 Aphonopelma mooreae

From the same import of 2022
View attachment 495256

1.1 Aphonopelma mooreae

Same male from 2022, female from 2024

View attachment 495257

This is brilliant, thank you for sharing this

 

[YellowBrickRoad]

@A guy , This is really awesome! You explained it so well and ugh, you're doing the right thing. It seems like there haven't been much posted like this. I mean there are little tid bits here and there; like, overflow the water dish, uhm, a little extra moisture if your T is about to molt or molting... and I'll add afterwards.

I've been keeping my Ts like this for a couple years now. Here are fresh pics of some Ts of mine including an adult female bicoloratum.

Some get a little more water than others, but you see the sloped angle that gets created by pouring water into the same corner everytime. And obviously you can see what is the moist substrate and the dry. The last time I put about 16oz waterbottle in the 5 gallons, less in smaller enclosure ect etc etc. Its been like a month+ I'm due to refresh some of them.

Anyway I have to go. Here's the pics. And great job on speaking up about this.



YellowBrickRoad

 

[A guy]

@A guy , This is really awesome! You explained it so well and ugh, you're doing the right thing. It seems like there haven't been much posted like this. I mean there are little tid bits here and there; like, overflow the water dish, uhm, a little extra moisture if your T is about to molt or molting... and I'll add afterwards.

I've been keeping my Ts like this for a couple years now. Here are fresh pics of some Ts of mine including an adult female bicoloratum.

Some get a little more water than others, but you see the sloped angle that gets created by pouring water into the same corner everytime. And obviously you can see what is the moist substrate and the dry. The last time I put about 16oz waterbottle in the 5 gallons, less in smaller enclosure ect etc etc. Its been like a month+ I'm due to refresh some of them.

Anyway I have to go. Here's the pics. And great job on speaking up about this.

View attachment 495259 View attachment 495260 View attachment 495261

YellowBrickRoad

Does your A. bicoloratum burrow?

With my husbandry, mine has a deep burrow and stays in her burrow 98% of the time. I almost never see her out but her burrow does have a nice big window view.

 

[l4nsky]

Lol, you've been way more disciplined about maintaining a control. I started a similar experiment between two different substrates instead, also using A. mooreae. I unfortunately lost my control being kept on my standard Aphonopelma substrate mix, but the experiments being kept on my standard Ornithoctoninae substrate have outgrown all other Aphonopelma slings.

The standard Aphonopelma substrate I use has a heavy organic content and is kept fairly moist as well. I'm getting great growth out of the majority of the 10 other species being kept similarily, but I'm looking to make the switch to my Ornithoctoninae mix for the majority during their next rehouses due to the results of this experiment.

I recently also found the time to respond to a series of comments I made on a YT video on Aphonopelma husbandry like a year ago. The channel owner has proven difficult to contact lol, but I'll cut out and place an excerpt on my theories behind my experiments here instead of putting out my own thread:

The working theory I'm using to guide my experiments with Aphonopelma (or more likely Dugesiella or some other long deprecated genus in the end) is based off the simple fact that most of these species are adapted to arid conditions. Animals that are adapted to live in arid conditions have evolved to take every advantage they can during the plentiful times and to be able to bunker down to ride out those times of famine and drought in between. The trick with Aphonopelma IMHO and IME is to try and keep them in this feast mode as long as possible and avoid exposing them to any temperature or humidity swing which could signal an upcoming time of struggle that they would enter torpor for. Again, IMHO I think if this can't be prevented, once they do enter into this state of torpor, it can be months before some unknown combination of parameters reawakens them.

Let me paint a mental experiment for you with two A. chalcodes slings. One has found a nice home under a rock in the middle of the desert. The second one has also made itself a home under a rock, except this rock is in someone's rock garden in the desert, next to a leaky fountain and under a dusk to dawn light that attracts and disorientates all kinds of prey. Do you think these two animals will enter torpor at the same time simply because it's a certain time of year as if they're using calendar? Do you think after a year's time, the first A. chalcodes will be the same size as the second one under the light? I don't think either of those scenarios is likely, do you?

I think the latter A. chalcodes will stay active for the majority of the year, taking advantage of the abundant prey and moisture to pack on size, whereas the former will probably be in torpor for the lion's share of the year as it waits for the monsoonal rains and the associated time of plenty. I think we as keepers need to try to emulate the latter scenario. By keeping captive Aphonopelma spp too dry for too long, I believe we're triggering them to enter into torpor and they won't leave this state until they've been exposed to a lengthy time of high ambient RH possibly paired with the associated barometric drop that accompanies the monsoonal season. If they're allowed to enter torpor (or potentially collected during/just prior to natural torpor) and the proper cues aren't given during the spring season to bring them out of it (which, let's face it are never given as the standard husbandry advice is keep them bone dry), I believe that's the scenario that leads to multi-year molts, infrequent feeding, and contributes to the phenomena where some species will wither away in a sealed burrow in captivity. They simply believe they're in an extended period of famine and are responding how they're instincts are instructing them too.

I also believe that when we are specifically talking about slings, it takes much less exposure time to dry conditions to trigger torpor as they have much less water to lose, a comparatively much larger surface area to mass ratio than an adult which results in a faster rate of evaporative loss, and a less developed waxy cuticle to restrict the evaporative rate. I believe this is what is causing the relative inconsistency of molt timing for slings that most people observe as they're quicker to enter the torpor state where they don't eat or hunt and the common husbandry advice is to just continue keeping them dry, further exacerbating the situation.

The situation is hindered even further because most people misperceive the Aphonopelma reaction of climbing the walls of the enclosure when exposed to moist substrate as a negative, stressful reaction to bad husbandry when in reality it's just their normal reaction to water, especially after it has been dry for so long. As I expanded on in the comments section of the YT video, desert dwelling Aphonopelma have a very complex relationship with water. Flash floods, which deserts are prone to when the monsoonal rains start due to the dry, hard compacted soils which initially inhibit absorption, can kill the tarantula in an instant, yet they need water to survive and will burrow to find cooler, more humid microclimates to weather out the driest parts of the year. Their first reaction to water is almost always to get away using higher ground. Once the substrate starts to dry, they will come down and eventually burrow after the moisture if they're provided the space to do so in captivity. It's important to note that there is a mod on AB whose own experiments with his collection and in situ observations of wild Aphonopelma in his area has shown they will even do this behaviour in the burrow, quickly climbing upside down to the ceiling once they sense water. Most of my adults are kept in haplotank style enclosures with foam rocks to burrow under, so I have readily available windows into their burrows and I've confirmed this behavior with my own specimens. His insights on the boards have been quite helpful to me as I've worked to better my understanding of the genus.

To put it simply and to quote another acquaintance who has seen a plain filled with adult male and female A. anax who were flushed from their burrows at the beginning of the monsoons and has seen similar results with his own captive Aphonopelma from similar experiments as mine, "I think the average hobbyist is told 'super hardy, just keep them dry with a dish and don't overfeed' not realizing that they're built to WITHSTAND harsh conditions, not exist perpetually within them."

 

[A guy]

Lol, you've been way more disciplined about maintaining a control. I started a similar experiment between two different substrates instead, also using A. mooreae. I unfortunately lost my control being kept on my standard Aphonopelma substrate mix, but the experiments being kept on my standard Ornithoctoninae substrate have outgrown all other Aphonopelma slings.

The standard Aphonopelma substrate I use has a heavy organic content and is kept fairly moist as well. I'm getting great growth out of the majority of the 10 other species being kept similarily, but I'm looking to make the switch to my Ornithoctoninae mix for the majority during their next rehouses due to the results of this experiment.

I recently also found the time to respond to a series of comments I made on a YT video on Aphonopelma husbamdry like a year ago. I'll cut out and place part of an excerpt on my theories behind my experiments here instead of putting out my own thread:

Same idea I have with what's happening. With Brachypelma, rainy season is the season of plenty, food everywhere and prey seeking shelter away from the rain and stumbling in tarantula burrows.

Constant "rainy season" could be a biological trigger for them.

 

[YellowBrickRoad]

Does your A. bicoloratum burrow?

With my husbandry, mine has a deep burrow and stays in her burrow 98% of the time. I almost never see her out but her burrow does have a nice big window view.

No, not at all, active, always eats. Molted once. She is almost always visible.

Uhm, I have a smaller one about 6yrs old, still 1.5in but I had it from a time when I didn't water. <4yrs now I've had it? I suppose I still haven't for it. It does have 3 water dishes though, one big one and two waterbottle tops.

I would say the small one doesn't eat much. Once a year molts. Doesn't burrow at all either. It did when it was in a deli cup though.

Lol, you've been way more disciplined about maintaining a control. I started a similar experiment between two different substrates instead, also using A. mooreae. I unfortunately lost my control being kept on my standard Aphonopelma substrate mix, but the experiments being kept on my standard Ornithoctoninae substrate have outgrown all other Aphonopelma slings.

The standard Aphonopelma substrate I use has a heavy organic content and is kept fairly moist as well. I'm getting great growth out of the majority of the 10 other species being kept similarily, but I'm looking to make the switch to my Ornithoctoninae mix for the majority during their next rehouses due to the results of this experiment.

I recently also found the time to respond to a series of comments I made on a YT video on Aphonopelma husbandry like a year ago. The channel owner has proven difficult to contact lol, but I'll cut out and place an excerpt on my theories behind my experiments here instead of putting out my own thread:

Boom! Folks! Knowledge! You're getting me all wound up over here. Every word of your self quoted quote is just about as right on as it gets. Especially the Aphonopelma sp. But brachys, nhandu, Grammastola, ugh.. these things love these conditions. Just reach the balance and they love it.

 

[TheraMygale]

Last year, during my personal quest to learn about substrate moisture, i came upon many posts by @l4nsky and @AphonopelmaTX, where they talk about observing behaviors that are different when not kept only dry.

this led me to dig deeper and find many posts, here and there.

your thread confirms what i, personaly, thought would probably provide better thriving conditions for Aphonopelma. I don’t have any yet; i have brachypelmas and grammastolas. I tried to experiment this with them. But not the same way.

i am definitely interested in this being explored more. I wish to one day have an Aphonopelma bicoloratum. But the slow growth and price… just did not justify the purchase for me at this time.

the more i will learn on the possibility of faster growth rate, linked to substrate moisture content, the closer i might get to acquiring one.

rainy season, for brachypelmas, is definitely a biological trigger. If it has an impact of their breeding season, then its linked to everything else. i think it has an impact on most slow growth tarantulas in the Americas. Especialy those that have extreme dry phases during the seasons.

it reminds me of the great African migration, where all the animals travel to get to that one spot.

 

[A guy]

Last year, during my personal quest to learn about substrate moisture, i came upon many posts by @l4nsky and @AphonopelmaTX, where they talk about observing behaviors that are different when not kept only dry.

this led me to dig deeper and find many posts, here and there.

you thread confirms what i, personaly, thought would probably provide better thriving conditions for Aphonopelma. I don’t have any yet; i have brachypelmas and grammastolas. I tried to experiment this with them. But not the same way.

i am definitely interested in this being explored more. I wish to one day have an Aphonopelma bicoloratum. But the slow growth and price… just did not justify the purchase for me at this time.

the more i will learn on the possibility of faster growth rate, linked to substrate moisture content, the closer i might get to acquiring one.

rainy season, for brachypelmas, is definitely a biological trigger. If it has as impact of their breeding season, then its linked to everything else. i think it has an impact on most slow growth tarantulas in the Americas. Especialy those that have extreme dry phases during the seasons.

it reminds me of the great African migration, where all the animals travel to get to that one spot.

I'll be trying this on my Brachypelma smithi since mine has been showing very slow growth.

Again, I'm not claiming anything but there's definitely something there.

 

[TheraMygale]

I'll be trying this on my Brachypelma smithi since mine has been showing very slow growth.

Again, I'm not claiming anything but there's definitely something there.

people have been doing, what has been, somewhat working for years. Why change things when its working? So i think we are moving past that, as we wish for better thriving conditions for our tarantulas.

there are so many people keeping tarantulas, compared to the number of scientists studying them, that together, we can definitely help each other out.

the goals of each party are different, but i think both share a desire for tarantulas to be thriving.

 

[A guy]

people have been doing, what has been, somewhat working for years. Why change things when its working? So i think we are moving past that, as we wish for better thriving conditions for our tarantulas.

Well, I do wish we are past that.

 

[TheraMygale]

Well, I do wish we are past that.

i think we are. And its what i find the most fascinating with tarantula keeping. We don’t settle for less, we research, we share and we are growing.

 

[A guy]

i think we are. And its what i find the most fascinating with tarantula keeping. We don’t settle for less, we research, we share and we are growing.

In here at least, these ideas and findings will be shunned in social media. With the typical "Who are you to make these claims?"

 

[TheraMygale]

In here at least, these ideas and findings will be shunned in social media. With the typical "Who are you to make these claims?"

social media.

its media in the end, like newspapers.

anyone can try anything and share. Its not like you’re saying: DO THIS.

its more of a, i am trying something based on things that happen in nature and these are my results.

 

[DystruktoBoi1]

So if I understand correctly, moisture encourages growth in at least your moorae examples, even though they are usually a "dry" species? Has anyone tried this on say, a chalcodes? I wouldn't mind seeing mine grow a little faster, but I've always kept the enclosure bone dry being a desert species.

 

[A guy]

So if I understand correctly, moisture encourages growth in at least your moorae examples, even though they are usually a "dry" species? Has anyone tried this on say, a chalcodes? I wouldn't mind seeing mine grow a little faster, but I've always kept the enclosure bone dry being a desert species.

No, the idea is the dry conditions that the hobby is keeping them in is not optimal, they're surviving, not thriving.

 

[DystruktoBoi1]

No, the idea is the dry conditions that the hobby is keeping them in is not optimal, they're surviving, not thriving.

Hmmmm I'm about to go soak my enclosure lol

 

[viper69]

I kept fish once more dry then normal and they turned into tarantulas- so anything is possible

 

[A guy]

I kept fish once more dry then normal and they turned into tarantulas- so anything is possible

It's actually funny you say that, I just watched a documentary about the evolution of animals in Chernobyl. It's not exactly fish to tarantulas but frogs in Chernobyl exposed to radiation rapidly evolved to become immune to radiation. Once a species of bright green frogs are now jet black. Their biology has evolved to produce extreme amounts of melanin that protects them from radiation.

They underwent evolution that should have taken hundreds or thousands of years.

 

[l4nsky]

It's actually funny you say that, I just watched a documentary about the evolution of animals in Chernobyl. It's not exactly fish to tarantulas but frogs in Chernobyl exposed to radiation rapidly evolved to become immune to radiation. Once a species of bright green frogs are now jet black. Their biology has evolved to produce extreme amounts of melanin that protects them from radiation.

They underwent evolution that should have taken hundreds or thousands of years.

Lol careful, quantum evolution is a slippery rabbit hole of a subject .

Here's another excerpt from the aforementioned email, which details my history with the genus starting in late 2022.

@A guy, you might even notice a reference to a DM we had a little over a year ago discussing our experiments with the genus thus far at the time .

In regards to my own collection and experience with Aphonopelma, I prefer to break it down via a simple indented list:

• 32 specimens representing 11 species (Individual species might be represented in multiple categories as I've pieced together breeding groups of different age classes and genetic lineages)

• 8 adult female specimens representing 6 species
  • 5 specimens were highly likely WC as adults
    • 4 of these 5 specimens have followed the same pattern. The initial molt in captivity was always variable and potentially long, but every subsequent molt once fully established has been yearly.
      • This includes the one female specimen in the collection who has been paired and bred successfully.
    • The problem child specimen is an adult female A. marxi. She settled in well initially and molted, however she was rehoused a few months later and has yet to establish a burrow in the new enclosure. I believe this inability to settle is a contributing factor with this case.
  • 3 specimens were WC as sub-adults and have matured in my care.
    • All 3 specimens are at 10-12 month molt periods

• 18 sling or small juvenile specimens representing 5 species
  • 1 specimen representing one species is confirmed US CBB as it was produced in the facility
    • The growth rate on this specimen has been phenomenal. When I stated that I have some specimens which might mature in under 5 years, I specifically had this one in mind as the likeliest to prove me correct. Sling molt records are often incomplete as I encourage all of them to burrow, but the first 3 molts appeared to be at 2 month spacing before slowly widening to the current 4-5 month period.
  • 7 specimens representing two species are believed to be CB or possibly CBB as they were legal MX imports as slings.
    • One species is A. mooreae from the second import to the US and the other species is A. pallidum, the only Aphonopelma sp listed on CITES, imported as slings and purchased direct from the importing wholesaler.
    • Growth rate has been fairly decent, especially for the larger growing A. pallidum slings, but the A. mooreae have shown a faster growth rate when kept on a substrate mix not intended for desert species.
      • This was actually a subject of experimentation between myself and another member on AB and our results were similar. In fact, I actually lost an A. mooreae sling kept on my typical Aphonopelma substrate mix as a control whereas the remaining specimens rehoused after months on the same mix to a mix intended for Ornithoctoninae spp absolutely thrived in comparison.
      • I'm slowly switching the other Aphonopelma slings to the Ornithoctoninae substrate mix as they need rehouses due to the results of this experiment.
    • Again, sling molt records are often incomplete, but these specimens appear to be on 4-6 month molt cycles currently.
  • 3 specimens representing 1 species are confirmed CH.
    • Collector confirmed these came from an egg sack collected with a WC female. These were slow to establish and growth rate has been relatively slow on the typical Aphonopelma mix. These are another candidate for future substrate experimentation.
    • Of all the slings, these have the least complete molt history.
  • 7 specimens representing one species are either confirmed WC or confirmed CH depending on year of collection.
    • Oddly enough, the WC specimens of this species have also displayed tremendous growth on par with the US CBB specimen of another species. Both species are actually highland dwarves, which is frankly surprising as well.
    • Once the initial molts occurred in my collection, molt rates appear to have started around 2 months before widening to the current 4 month period
    • The CH specimens have only been in the collection for a little over 3 months, but all have molted once and appear to be just as vigorous as the slings collected the prior year. The WC specimens were just transferred onto the Ornithoctoninae substrate mix from the Aphonopelma mix this past rehouse, so I'm anxious to see if their growth rate improves in line with my observations with A. mooreae.
  • The remaining 6 specimens are mature males, subadult males, or subadult females.
    • Most molts are between 6-10 months apart for the subadults, which the occasional penult male taking much longer than that.
    • I have one problem child in this bunch as well, a subadult female A. peloncillo. She has an established burrow unlike the A. marxi, but I'm second guessing the validity of the sex of the specimen. These apparently are more difficult to vent sex and its size would be penult if male, which would explain the increased length of the molting period as I've made that observation with other penult males of other Aphonopelma species.
      • The other option, which I'm really hoping it's not, is an Acroceridae spp larvae is currently consuming the spider's internal organs, as sadly I also have experience with those parasites in another Sky Island Aphonopelma species that was WC.

LPT: click on forum quotes in order to expand them and fully read lol.