Thank you on the case of the gallons.
In this tank you could keep maybe 2 couples of dwarfs,depending on the species you want.
South-American dwarfs are very nice,and you could chose for a species that breeds in caves and one species that likes to breed in the open areas of the tank.
Use always a lot of decorationmaterials in your tank,and surround them with real plants,no plastic please.
Use wood,stones(rocks) and little flowerpots if you want.
You can make these look more natural when you put siliconglue(a kind that does not afflect the waterquality and is not poisonous, to the fish)on the flowerpots and add peat(torf)peaces to it,or use good cleaned coconutshells.
A choice for S.America could be Apistogramma cacatoides and Laetacara dorsigera,or maybe Apistogramma agassizii with Microgeophagus ramirezi,or Nannacara anomala with Apistogramma borelli.
This are just some possibillitys,but i think those are good fish to start with.
For africa-dwarfs i like to suggest Pelvicachromis pulcher or p.subocellatus with Anomalochromis thomasi or Pseudocrenilabrus multicolor or P.nicholsi.
Important is that they all can form their own territories,and it will help if you put something in the middle of the tank(in case of 2 species),so that the cave-breeders take one half of the tank and the species that lay eggs on substrats(wood or stones) take the other half.
You should be giving them 80% life-food(tubifex,larves of midges,artemia,dapfnia) and the rest dry-foods and frozen food.
The waterchemics for most of these fishes are not very important(extremities excluded).
Feed them 2 times a day in small quantities,so that they can eat this food in 5 minutes.
For compagnion you can give these fish some life-bearers like guppy's or some tetras,some little Corydoras species goes well to.
every week you must make a waterchange from minimum 25%,with water of the same quality,the temperature can be a little bit colder(1 or 2 degrees C.).
You will see that this helps to keep your fish in good condition and active.
A lot of times your dwarfs will make a start for breeding after this waterchanges,because it assumes the coming of rain,what in nature means that a time is coming with plenty of food for the fry.
The temperatur can be something between 24 and 28 C.
In a little tank you can put a little filter inside,which you clean every 2 or 3 weeks.
See that you clean the things inside the filter in water from the tank,so that you don't kill all the good bacterias inside.
Put all the new fish in the tank at the same time,because when you put one species of dwarfs later inside,they will not often get the chance to form a territory anymore.
Dwarfs like shadey areas,put some surfaceplants in and not to strong light.
I hope this is for now enough information.
If you need more,only ask,maybe i forgot something,good luck Willy Bijker,Holland.
Willy,Male,Holland,Dwarfs,West-Africa,Central-Amerika,South-America,Tanganjika,Author of articles,Give lectures to.