The container I chose is 2 1/2 gallons, almost-clear plastic, tall and
round, with a lid that will seal tightly when the time comes. 2 1/2 gallons
should be large enough to avoid temperature swings, considering the
container is next to a large aquarium in an air-conditioned room. The total
water volume is 1.8 gallons, with about 1/2 gallon of air space at the top.
I added 1/4 teaspoon of marine salt mix, to supply trace elements that might
be in short supply. This small amount of salt shouldn't hurt anything, I
hope. I have the lid on loosely, to allow air circulation but prevent any
"critters" from escaping. I plan to put the lid on tightly in about a week.

The substrate is 1 inch of used 1/8 inch aquarium gravel, mixed with 2
tablespoons of mud from a puddle in the yard and 2 tablespoons of mud from
the river nearby. This should provide enough "seed" bacteria and other
microorganisms. A few old snail shells are mixed in the substrate, and I put
in a small piece of limestone to provide calcium and prevent pH crash. There
are also a few small sticks, to provide refuge for the bacteria and to give
the snails and other animals something to climb on.

The plants I included are a 2 inch bunch of Java Fern, 6 pieces of hair
grass, a 1 inch piece of hornwort, two 3 inch hygrophila plants, about 30
leaves of duckweed, and small bits of several types of algae. I only
intended to use about 10 pieces of duckweed, but that sticky $#*! didn't
cooperate.

There are also two tiny "mystery plants ???" which came in with the
duckweed. I hope this is enough, and the right kinds of plants to provide
the animals with food. The total weight of the plants is about 2-3 ounces
when they are out of the water.

The animals I included are two small ( 1/4 ") pond snails, two small (
1/4" ) ramshorn snails, a few tiny worms, and a small black beetle. I don't
know if the beetle is terrestrial or aquatic, but I found it crawling on the
duckweed. There are probably other small organisms that came in with the
duckweed or mud, but the water is still too murky to see very well. The
turbidity should pass soon, I hope.

My LFS had ghost shrimp in stock yesterday, so I can probably add a few of
them when I get back to town on Thursday. I'm tempted to include a small
fish or two, but I doubt they would survive long.

Does anyone have more ideas or suggestions ?

I will give an update on Thursday, when I will hopefully add ghost shrimp
and a few other things.

Limnophile