It's all in our sig, but it's 180 litres with 26 fish, in my opinion and also many others overstocking is best for this type of fish, we have excellent filtration, surface agitation and we are regularly performing 20% water changes.
We have only had 1 casualty so far which was an unknown fish which I saw in the LFS, it was in a bad way there, but I thought he would pull through, unfortunately not.
We have regular mating dances, and two of them were holding fry in their mouths (with no success); as juveniles they do practice, so we are not too worried about that. Just having them breeding is a sign that they are comfortable and doing well.
We have three dominant males in this tank, each one keeps his own little cave and regularly patrols the area (Especially when a female swims by

)
These fish are incredibly entertaining and colourful, you could watch them for hours!
I am not saying we are experts, there is always something to learn, but I do think we are competant fish keepers.
Sorry about the rant, you only asked "what size is the tank?" and "how many fish?"
Just wanted to let people now that we havent just bought a tank and stuck a load of fish in there!

good luck to anyone that has!
Rich