@ Cerat

I have seen the same with my A. avicularia slings they also don't have any ventilation

They are still small but they are kept in the normal little tubs with NO ventilation holes

I wet the substrate and let it dry out and then I'll wet it again.

I try not to let my room temperature drop below 20degC

All of them are doing really good and I have not had any loss so far.

I don't know if the same holds true for other avicularia species

In my opinion normal A. avicularia is a bit more hardy than some of the other avicularia species.

Would be nice to get some feedback from other members regarding some other species.

My first versi was in a small tub as a sling but with lots of holes. Moved it to a small glass tank (long with a ventilation hole on the lid). After a year I moved her to the same looking tank only bigger and longer, after a month it died. I say the tank was to long and didn't ventilate to the bottom where she normally was. My soil not to wet and I spay tanks 2x day. Will also be putting heating pads on next to the cage as its getting cold.

That's what has me stumped by these strange creatures we call spiders.
Mine has almost no ventilation, too moist and cool temps. Exactly opposite what Avics "should" have.

Avicularia avicularia
Avicularia azuraklaasi
Avicularia bicegoi
Avicularia braunshauseni
Avicularia diversipes
Avicularia purpurea
Avicularia sp. "Purple Peru"
Avicularia geroldi
Avicularia laeta
Avicularia metallica
Avicularia minatrix
Avicularia urticans
Avicularia versicolor

I raise all my slings in a small pill tub with only 4 or 5 holes in the top, line the tub with tissue paper and spray it wet. Tissue paper will show dirt very quickly which can be changed. The main thing is so they are forced to eat and are in a small space where they can catch their meal easily. With time I train them to eat from the tweezers, this way insuring they eat.
After their 5th instar they move to a deli cup turned upside down, with only cross ventilation, 4 holes on opposite sides. They get a bit of plastic plants glued to the side to attache their webbing and a bottle lid filled with water. Spray them once a week as well.
Once they outgrow this the move to a bigger 500ml tub done the same, upside down.
Sub adults move to 2lt sweet jar with turn lid and still upside down, cross ventilation but now I add some holes to the top as well. The bottom gets a 125ml deli cup filled with water.
Adults move to a glass tank with front door, cross and top ventilation. Only some of my older Avicularia sp. ever get substrate. If they have no substrate a good water bowl with large surface space is important.

Why don't you use substrate? Can you maybe post a few photo's of the different cages and tubs you use?

Anne wrote: Why don't you use substrate?

I'm assuming he does this because there is no need as they are strictly arboreal.

My versicolor died two days ago, stuck while molting