Question
 I have some semi and aquatic plants (indoors) in a plastic window planter that I want to move to an aquarium and add fish and maybe shrimp. (Overhead fluorescent/grow lights currently maintain [winter] air temps 65-78F, Summer would be maybe 10-15 degrees warmer, worst-case. I have no idea how that might translate into water temp)
Your websites convinced me that Rosy Red Minnows are best, but they are unavailable locally, and the smallest online order I have found is for 100 --- I'm thinking maybe a dozen max could survive in the 15-20 gallon aquarium I just bought used. I'm wanting fish (shrimp?) that will control algae and mosquito and hopefully fungus gnat eggs/larvae. (And not eat or otherwise damage the plants.) And it would be nice if they could live off the oxygen the plants themselves supply, so I don't have to buy/run an air pump.
/thank you very much/Love your Rosy Red Webpages/Don~~/

Answer
You are right, you don't want 100 rosy reds in there.  I suggest fewer than a dozen.  Have you asked your local aquarium store if they can order some (and sell the extras to other patrons)?  If not, perhaps you could find local aquarists and/or ponders who want some of the rosy reds that you order.

Rosy reds can get along with most docile shrimp.  Some shrimp algae but others don't.  Shrimp aren't normally going to control algae in a tank because they don't eat much.  A trapdoor snail might be better for that.  Shrimp won't eat mosquito larvae but the rosy reds will.  If the tank is indoors, why do you expect mosquitoes?  Fungus gnats are on terrestrial plants, right?  The aquatic animals can't get to them.

A small filter and aeration is always a good idea but the rosy reds and shrimp may survive without them.  They certainly will do much better with some water filtration and circulation.  Only submerged plants will add oxygen to the water (and only during the daylight).  The emergent vegetation won't effect the oxygen levels.  Even if you have say a lot of anacharis under water producing oxygen during the day, at night, it will use oxygen, and the fish and shrimp may not get enough.

Good luck Don!