Eastridge107

I Changed My 29 Gallon 100%, About Three Weeks Ago. Pleco, Molly, Loach, Neon And Several Zebras Are Dead. Remaining Fish In A 5 Gallon Temp Tank. I Used 25 Or So Gallons Of Distilled Water And Treated It With Aquarium Solution Ultimate Water Conditioner. Everything Appeared Perfect, Until Three Days Ago. Rust Appears To Be On The Plastic Plants And Ocean Coral. Any Suggestions?

TheEssigs

I dont think you have rust... i think you may have brown diatoms.

(dont worry, although unsightly, its harmless to your fish)

sirdarksol

You changed everything all at once?
My guess is that you broke the nitrogen cycle.
(read herehttp://www.fishlore.com/NitrogenCycle.htm)
Your tank started over, and those fish likely died of ammonia poisoning.
Did any of them have red spots on their gills or bodies?
It took about two weeks for my guorami to die of ammonia poisoning, so three weeks is about right.

You should really change the water in increments. 50% at a time is the most I ever do at a time, though even 75% is probably safe. 50% a week is considered an excellent amount, no matter how you break it up. (all at one time or 10% on five different days)
Also, did you change filter media or sanitize the thing when you changed the water? Even with a 100% change, it seems odd for this to have happened.

Eastridge107

Any Advice On How I Proceed. Is It A Mistake To Use Distilled Water? Where I Live, Even With A Water Softener, The Water Is Very Hard.

Mike

I wouldn't use distilled water - it would be lacking major and minor elements that your fish have become accustomed to and need for osmoregulation. The difference in water parameters is prolly what did your fish in - pH, temperature, GH, etc.

Also, distilled water is considered virtually "pure", meaning that there shouldn't be any impurities in it such as chlorine and chloramines, so a dechlorinator wouldn't be necessary with distilled water.

The fish you listed (except the neons in my opinion) are considered fairly hardy fish and would probably be ok with dechlorinated tap water. And like theesigs stated, the brown diatoms are normal and might go away once the silicates are used up. Regular, small water changes will do wonders.

What I would do is 10% water changes (with dechlorinated tap water) in the 5 gallon holding tank every 12 hours. You can get the 29 ready to go by replacing the distilled water with dechlorinated tap water in the meantime. Once the 5 gallon consists of all water from your tap you can add them back into the 29 gallon.

Hope your remaining fish make it.
Mike

Mike

Also, I'd look into getting some bio-spira in case your tank does go through another cycle and test kits so you can monitor your parameters (pH, ammonia, nitrites, nitrates, etc) and post results here so we can help ya better. You mention that your water is "hard" but what exactly is the pH and hardness levels?

sirdarksol

All excellent advice.
And sorry, I also meant to add "good luck with the rest of your fish. Keep us posted and we will do our best to help you."