bubbles on our fish

Question
Hi there. I changed the water in my tank today and since then have lost 4 fish and the others are looking poorly. There are a lot of small air bubbles coming from the gravel and the fish also are covered in small air bubbles. Do you know what this could be as it has never happened before. Thanks

Answer
Good evening Kelly, thank you for your question...

Hmmm...I have to be honest, this is a first for me. That you lost 4 fish immediately afterwards indicates that something is very wrong. Did you use dechlorinator in the water? Did you add any additives to the water such as salts or buffers? What is your gravel composed of, what does it look like? How much water did you change at one time?

I happened to be online when you wrote so I wanted to answer your question as soon as I could. Please write back with these details, as much information as you can provide about your water change and the background of your tank - such as when you established it and what is in it, the kinds of gravel and fish in the tank. Somewhere in there will be the clue that will unravel the mystery for me.

Right now I recommend you test your water. Ammonia or nitrites may be present in your tank, these levels must be at 0 ppm - always! Any detectable levels cause ammonia poisoning, which cause redness around the gill area, burned fins, gasping at the surface for air...and sudden death. Usually the recommended "fix" is a water change, but hold off on this until you determine what is wrong with your water. Test your straight tap water, if you can. Does it smell any different than usual? Unless you changed 100% of the water, there should be no reason for such acute distress. If you changed 100% of the water, then you undid the cycling of your tank by removing all of the beneficial bacteria that was in your water. There may not have been enough beneficial bacteria in the filter media to compensate for such a drastic change. This still doesn't explain the bubbles...you don't, perchance, have an airstone that may be making contact with the gravel? It's awfully strange...

Please write me back with more information, I will try and reply tonight if I can. Sorry to hear the terrible news.

Nicole