[What to do after removing sick fish?]

I have setup a quarantine tank and am treading some fin rot with meds. What do I need to do, if anything, to the tank the fish came out of? 

[Cory! International shipping!]

Cory, 

I have heard you talking about international shipping rates. Have you ever looked at the simple export rate from pirate ship? That is all.

Thank you 

[20 gallon hex filtration and water movement]

The tank is cycled and the test have been consistent and good. It is stocked with: 

1 female German Blue Ram 

4 Domestic swordtail (2 male 2 female)

3 panda cory

3 glowlight tetra

1 juvenile albino Bristol nose pleco

Some ghost shrimp 

 

[20 gallon hex filtration and water movement]

I'm using a fluval hang on back filter in my 20 gallon hex tank. This tank is approximately 20 inches deep from the top of the water to the substrate. With the flow set to max I am getting to much water movement at the top and barley any toward the bottom. I have put and extended tube for the water intake to get near the bottom. 

Should I run a small sponge filter with the hang on back filter that I have? Or should I switch to just a large sponge filter?  Or any other suggestions? 

[New to plants need some guidance]

Thanks everyone for the info. 

[New to plants need some guidance]

@Aubrey Is that the "A Fishkeeper's Guide to Aquarium Plants" by Barry James? 

[New to plants need some guidance]

I am new to plants and would like to know some good resources for identifying deficiencies. I think that this one in particular is a magnesium deficiency. I have started to dose weekly with Easy Green. Should I snip these leaves off at the base?