Air pump death

Question
A few years ago i installed an air pump with the air wall (along the bank of the tank) attachment.  The very next day i woke up and ALL of my tetra neons (12) were dead.  I was devastated especially since my tank was pretty well established (maybe 1 year).  I immediately removed the pump.  All of my other fish, who had also shown very worrying signs that day, recovered quite well (although i think i maybe lost another one or two the next day, sorry can't remember, was a long time ago).  As the fish had recovered i stupidly reinserted the pump (thinking millions of people must buy these and i had heard no horror stories).  The next day more had passed and after removing the pump again it was too late, after a couple of weeks my fish were pretty much wiped out.  My tank was emptied and has lay dormant ever since (apart from when i went off to Uni and my mum got goldfish in place of me then cleaned the tank with the kitchen sponge and killed them all, she was devastated!!!).

Anyway, my question is, Do you think it was merely the stress of the mass amount of bubbles in the water that got to them?

I think it must have been either the stress or air pollution.  I am thinking of setting the aquarium up again and would like to have this air pump feature in it.  I wondered if you had maybe any experience of this happening or had heard of anyone else who has.

Thanks for taking the time to read this.
Ally
Scotland

Answer
Hi Ally,
Wow, a very interesting (but sad) story. I've never heard of an air pump/air wall causing such drastic fish deaths.

Its very difficult to determine what might have gone wrong, But I think you may be on to something as airpumps can most certainly introduce air pollution from anything used in the house. Perhaps chemicals from a household product.
The bubbles themselves are unlikely the cause for the sad event.

I would set the tank back up and introduce 5-6 Zebra danios as your "test fish" keep in mind when you do first setup a tank that the fish will be producing ammonia. And the special bacteria have not yet had a chance to get established in your aquarium as your "biofilter" to take care of the ammonia. So you should keep only your "test" fish in the tank for at least a few weeks at first to allow the bacteria time to establish and be sure to never overwhelm the tank by immediately adding a large group of fish.
The bacteria get rid of the ammonia in two steps. First, one type of bacteria eat the ammonia and convert it over to nitrite--which is still dangerous to fish. Later, a second type of bacteria eat the nitrite and convert it over to safe "nitrate"
This process of the two types of bacteria establishing takes 6 weeks--sometimes more or less.

Try to test your water on a daily or every other day basis for ammonia, nitrite and nitrate to keep tabs on how the water condition is and how far along the tank is in established or cycling.

You may already know all of this but its well worth mentioning.

Make sure your arms and hands never have soap or any other chemical residue before you put your hands in the tank. Try to remember to rinse them well under running tap water as a precaution.

You may try observing if there are any air freshening or cleaning products being used a lot around the tank or in the room, if so, try to limit it or move the tank somewhere else in the house.

I do hope this helps!
Karen~