Another 20g stocking question

[themusician]

I read the earlier post about stocking a 20 gallon tank, but I would like to stock mine a different way and I'm wondering how much is too much. I've been reading The Simple Guide to Freshwater Aquariums, and the author suggests the following stocking scheme for a 29 gallon tank:

3 platies
8 danios (or three schools of 8? I'm a little confused with the way the paragraph is worded, but the latter seems like a LOT of fish!)
6 lemon tetras
4 cory cats

I chose this scheme because I really like the platies and I really like the cory cats, but these numbers are meant for a larger tank. How many fish should I remove from this list to make it a safe stocking scheme for my 20 gallon? Any substitutions I should consider?

[gm72]

That stocking may actually be okay as long as you have adequate filtration and perform at good weekly water changes.

So, what is your filtration and projected tank maintenance schedule?

[themusician]

I have an AquaClear 50 filter and intended to do a partial water change once a week, but I can be flexible on that if I need to be.

[zackish]

That should be fine. But keep in mind you don't NEED to go with that. You can take out the platys and throw in some more of the tetras or perhaps even a whole different group of tetras, taking out the lemons.
You have the main idea though, stick to 2 smaller schooling fish groups and then some corys. Maybe a couple otoclinus too to clean up the algae.

[kimmers318]

The best way to figure out what stocking levels your tank can handle is to go slowly and monitor your water parameters.
If you start with a fishless cycle you can add quite a few fish, even fully stock right off the bat. Your bottom fish, such as cories, are not going to get in the way of your danio's much, leaving both plenty of room of their own. Platies in my experience have a tendency to utilize most of the aquarium, although they don't really seem to set up any specific territories.
Start with the smallest stocking level that you feel would work, and watch your tank for a couple of weeks. Set up your weekly maintenance schedule and check your water parameters before your water changes. If your nitrates are staying at 5 or less between weekly water changes you can usually safely add more fish, if you are seeing higher nitrate levels than say 10, you probably don't want to add more unless you want to increase your filtration and/or water changes.
Different fish will have different needs also, so always research. I have 3 c. irrubesco in a 29 gal tank. These guys only get to around 2 inches, but need such a large tank because of their aggressiveness. The nitrates in that tank won't hit 10 in 2 weeks, but they have to have that kind of room or they might tear each other up.