Sterilizer Bio Filter really needed or are there chemicals to clear up

my problem? I had a few goldfish in there until we added algaefix,
afterwards within a day the fish were dead.


** Please find another way other than chemicals. I have two UV lights
and
haven't used or needed them in several years.
--
Yep imagine how I felt when I walked outside and found dead fish
floating. I don't use chemicals on my indoor aquariums anymore either.