Would anyone like to elaborate?What your rule of thumb for the fauna:tank size, assuming we are talking about small schooling fish? Do the shrimp carry the same "weight" as fish when it comes to the bioload?
Personally, I consider the mass and activity level of fish when trying to determine acceptable stocking levels. How many celestial pearl danios does it take to weigh as much as a full-grown angelfish? 100? Maybe more? The little danios are perhaps a bit more active so I wouldn't get too carried away.
In a 20g aquarium you can easily keep 3 or 4 dozen small schoolers. If you use bigger fish, like rummynose or harlequins, I'd limit it to 2 dozen or so.
That's just me though.
You could keep hundreds of the little shrimp like CRS's. Amanos probably count the same as a rummynose, at least when full-grown.