emperor

So yester ay i went to my lfs and purchased a school of 8 rummynose tetras for my 20 gallon.. and the guy was pretty chill he gave me 9 for the price of 8 so i got an extra for free, but when i got home i realized on top of the 9 rummies he gave me 2 blue emperor tetras that were bieng sold in...

I purchased this particular filter about a month ago. I had not used it up until today. I did as it said in the instruction manual and added water until it over flowed into the aquarium, I then plugged it into power and it kinda gargled for a little while (which I assume means it was gaining...