# Oops, I killed my Cichlids



## Mushtang

I've had a 55 gal Cichlid tank for about 15 years, at various locations - not with the same fish. Over the years I've done my share of water changes, filter changes, swapping out tank decorations, etc. and I've found what works and what doesn't.

When I first got the tank and would do water changes, I'd be sure to add some dechlorinator to the tank when filling, but over the years I've found out this isn't necessary. I can change out about 1/2 of the tank and the fish don't have a problem.

However, two nights ago I had something happen for the first time ever. I did a 1/2 tank water change, I cleaned the filter (Fluval cannister), and I added a large rock (that had been in that tank before) - an hour after I was done all 5 of my Cichlids were dead. 

My best guess is that the fish were in shock due to the temperature change, even though I tried to put in water that was the right temperature. But perhaps it was a combination of the shock, the chlorine, or maybe there was something on the rock decoration that I wasn't aware of that poisoned the water. I was careful not to rinse off the ceramic tubes in the filter which would have killed off the good bacteria, but the fish died too quickly for that to have been a factor anyway.

Now there are 5 big gold fish in the tank in order to keep the bacteria alive while I decide if I want to keep Cichlids again or if I want to take this opportunity to just have a Tropical Fish Tank for a while.


----------



## Crazy

It sounds to me like you not declorinating the water killed the bacteria in the tank, which would have caused the clorinated tank to crash from a lack of bacteria. However it happening so quickly suggests shock, possibly from using colder water during your water change. Chlorine and Clhloramine are toxic to fish and bacteria, I recommend using dechlor any time you change any amount of water as chloramines do not evaporate and will build up to lethal amounts anyway.


----------



## Summer

yea not dechlorinating is not a good thing. It's harmful to the fish, and harmful to the benificial bacteria. the chlorine will kill off the bacteria allowing the ammonia to rise again. Your water company may have also added something recently that killed them.


----------



## navigator black

Springtime... I lost two tanks of fish a few years ago when my municipality decided to chemically flush the lines. It was safe to drink (they said) but it slaughtered fish. At this time of year, that is a possibility.


----------



## snail

Yeh, chlorine amounts in tap water tend to vary. The type of treatment can also change. Are you using tap or well water? Do you let your water stand before you use it?


----------



## jrman83

Why would you ever risk your fish over a capful of dechlor? I hope you have changed that idea. Just because fish don't die, doesn't mean they aren't affected by what you do or don't do.


----------



## JohnniGade

Never had any chlorine problem in Denmark? Never dechlorinize my tapwater.


----------



## snail

All tap water is treated but if only chlorine is used letting it sit for long enough (1-3 days) will get rid of the chlorine. Using water straight out of the tap without sitting or being treated can kill your fish and even if it doesn't chlorine burns skin and gills so it is a bad idea.


----------

