Question
Dear sirs: I saw your site and thought that you might be able to help...we have a pond outside approx 6feet long by 4feet wide by 4 feet deep...between the koi and gold fish and huge Plecostomus we had wholesale about $700 in fish ( I can't give you an specific number) ....we winter the fish every year in our finished basement in a pond 4ft x3ft x 3ft...we have never had a problem....fyi ...we have pumps and bubblers , water plants..blah blah blah....we have done this same thing for the past 4 years...we also have two red slyders..that the community college winters for us ( big guys)...and some trap door snails..that the turtles had not eaten.....the fish  have been in the inside pond for almost 2 months...we live in Minnesota. .I feed the fish that day like always and they were fine....then we have a halloween party...a huge one...they are locked where they live all winter in our huge laundry room pond...when we got up the next morning there was a stench through out the house.. we went into the laundry room and every single fish..including minnows were floating dead....the only thing we did differently was that we had a fogger in the basement running for about 6 hours for the halloween party...it uses a product called fog juice..the Plecostomus lasted anouther day then died also....the fogger solutions says nothing about being harmful to fish..or animals...it does say that people with asthma should avoid it..what happened have you ever heard of this problem.?...one individual told me it had to to with nitrogen and carbon dixoide....I would appreciate any info....I am heart broken...thanks for your time and any info....we have a cat also..it is scary if the solution is killing things..thanks you for your time and any info...if you do not have an answer ...can you send me to someone who does...many thanks  Rhonda

Answer
It is a heavy CO2 concoction that creates that fog... so basically that is what killed the fish, etc.  The fog is deadly because it is not only absorbed by the water but when the fish go to the surface to gulp air... they breath in fog... I am sorry this has happened to you.  It sounds like it was a freak accident.  I would write the company and the FDA to ask that a warning label be put on such products.  dave