If you think about this question in general, how many fish can we add to a tank, it's really a good question.
What might it depend on?
filtration/flow
Water changes
Species of fish
Food, feeding frequency and type
Plant density/growth rates
I have a 20 gallon,
250 GPH
110w
CO2, dense planting
1-2x a week 60% water change
feed 2-3x a day, worms and flake
15 coral ark pencil fish
42 Cardinals
18 cory panda
30Amano shrimp
At least 20 cherry shrimp
15 Blue shrimp
6 clown Killis
And recently added 16 King emperor tetras.
I'll remove the King's, that adds a bit too much
But the tank has been running well for months and I just recently added the kings.
That's a pretty heavy bioload.
But it's well cared for and the fish are small, and yes, EI dosing routines+ ADA AS.
Regards,
Tom Barr