20 gallon aquarium stocking beside Flame Tetra?

Ok everyone, so far in my tank I have the following
4 platy
2 feminine swordtails
3 von rio tetra ( aka Flame Tetra)
2 pygmy cories (dwarf corys)

The tank is filtered with a filter for 80 gallon tank, so its overfiltered.
Knowing this, I want to add a male swordtail, but also 2 more Von Rio tetra (raising the number to 5) and maybe a few more pygmy cories.

I do wet changes often, and I have places for the swordtail fry, whether I should get any...

What do you think?
My pale tang have some white fuzzy...
Answers:    thats pushing the stocking limit a touch bit but may work out ok, if you do add anymore fish make certain to add the teras since they need to be in a university. Theres really no such thing as overfiltering, having a bigger filter is never a bad hypothesis
How frequent gallons does a congo puffer...
no offense but thats MAJOR CROWDED SENOR kmon u want 3 golfish in 10g max
What are the tiny moving brown spots one my fish reservoir walls?   I enjoy two piranhas and i simply hold a 40L container im not certain what temp to set the reservoir till i receive a bigger container ?   Crayfish thoroughness and abet?   How plentiful dampen change do i requirement?