> 1. Do Nepenthes obtain all necessary trace elements
> from prey, or are some minerals taken up by the roots?
> ...perlite holds a huge amount of water but is very
> open and airy. Orchid roots seem to love it, and I was
> wondering if Nepenthes might like it too. The advantage
> of perlite is that it doesn't decompose and rot roots. The
> disadvantage is that it doesn't decompose and release
> nutrients. Could I grow Neps in such media?
I've found that Nepenthes can grow just fine without catching
prey in their pitchers. Of course, I try to give mine good
lighting. I rarely fertilize.
With regard to potting media, you'll get a variety of
answers/preferences to this question. Referring to orchid
roots is a mistake, though. Orchids like to have their roots
dry out somewhat between waterings. So a potting mixture that
drains well and doesn't stay saturated with water for long
is good for them. (I'm a bit surprised by your claim that
perlite holds lots of water. Water drains right through
the perlite I have).
Nepenthes like to have their roots in a moist environment. The
roots should never dry out, according to my experience. You'll
find that Nepenthes roots are very different in appearance from
orchid roots. Don't treat them the same way.
I use long fiber New Zealand sphagnum mixed with a generous
amount of perlite and the plants do fine. Like I said before,
though, you'll get a lot of different opinions on potting
media (from Cliff Dodd, Mr. Mirabini in Germany, etc.)
> 2. Are there any Nepenthes species that remain
> compact enough to reside in an old aquarium that is
> 24 inches long, 12 wide and 16 high?
There are Nepenthes which are less vine-like and more
compact, but why does this matter? If your Nepenthes
grows too big for the aquarium then cut it back. Root
the cuttings and then give away plants. Your mother plant
will sprout new growth. N. alata can grow like a weed
and will surely outgrow the aquarium you described.
Perry Malouf