Sorting a csv file on a particular field

I have below csv file, which have around 5k lines in following format:

ABC,12345,test.com,56780,0.00,200.65,0.00,0.00,200.65
XYZ,54311,tset.com,69540,0.00,102.32,0.00,0.00,102.32
..
...

I wanted to sort this file on field6 so that i could extract my desired lines from the csv file. I did use below command which sorted my csv file on field no 6:

sort -n -r -t, +6 -7 vishnu.csv

-n Specifies numeric field
-r Reverse sorting
-t specifies seperator (here , is a seperator)
+6, -7 specifies column position

sorting the csv file if separator is tab
sort -t $'\t' -k5 -nr filename