Death by water change

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Aaron10020

Aquarium Advice Apprentice
Joined
Feb 22, 2018
Messages
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I've been having issues with fish deaths after doing 30%+ water changes. I typically do about a 10%-15%water change a week. On occasion I'll do a larger one when ammona creeps up. A few time when I've done this I've lost a fish or two (always my Florida flag fish). No notable water parameter changes and I let the water sit for days in 5 gal jugs to temp balance.

Tank is 125 gal planted about a year old
Stock
-1 5in bluegill
-12 flathead minnow
-1 gorami
- was 6 Florida flag fish now down to my last 1
-3 mystery snails
-1 brisle nose pleco

When this happens I observe no signs of stress from any other fish not even the surviving flag fish.
 
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Hello Aaron...

By routinely removing and replacing only 10 - 15 percent of the polluted tank water, you're maintaining a specific water chemistry. Your fish have become used to living in water with higher nitrogen. By suddenly changing out twice the old water, you've changed the chemistry suddenly. This is deadly to most aquarium fish. Your removing and replacing more tank water is a good idea, but you need to make these changes gradually.

Ideally, you should be changing out at least half the water every week to maintain healthy water conditions. But, this needs to be done over a long period of time. Each week, change out a little more water and then a little more and so one. Your fish won't notice a gradual change in the water chemistry. A sudden change obvious to you or not, is very stressful and deadly as you've noticed.

B
 
Hello and welcome. I can't imagine how Ammonia can creep up in established tank, especially planted. Why do you believe this to be an issue behind the deaths? What is the idea behind letting the water sit in jugs for days? What filtration do you use?
 
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Maybe you should be doing 30% water changes all the time and not sometimes?

Maybe letting the water sit for days is causing a bad bacteria to form in your buckets?

I would get a hose for your faucet that has hot and cold in your home. Get a digital thermometer and set your temp as you fill the buckets from the hose on your sink, treat the water with dechlorinator and add the water to the tank immediately afterwards.
 
Aaron, with a matured cycled tank, serviced with proper water maintenence and careful feeding, the ammonia should never creep up. That might be a good spot to start your investigation. Your Florida Flag fish might be suffering to the described chemistry fluctuations occurring in the water.
Might try 2x 20% - 25% WC's a week. It's a lot more work but it's likely to pay off.
 
Thanks for the input and your probably right it was my first thought as well. Only issue is it dosent always happen and as noted theirs really no notable change to my parameters they stay pretty stable and its only the flag fish. Must just be their the weakest link. Just floating this out there in case theirs something else I was missing most everything in the tank is pretty hardy their likely just the canary in the coal mine.
 
Heavy feeding periods when I'm off work longer streches
And it's got a hydor 250
 
*350
It's either a peramiter shift from the unusual wc volume or some trace elements I'm my tap that I don't know to look for.

As far as the storage of the water it's in food grade storage containers and nothing but dechlorinater and tap water have ever touched them. I use them for the smaller water changes and have had no issues.
 
I would think a parameter shift would affect more of your fish.

I'm not so much concerned with what you use to do your water changes (storage containers) but rather it sitting at room temp for days. Sitting water produces bacteria (microorganisms) that typical chlorine levels in tap water won't even control. Also carbon dioxide in the air mixes with the water and lowers the pH. Like I said, I would try to find a hose attachment for your sink faucet at Ace, Home Depot, or Amazon with a digital thermometer to match your tank temp.

Also, I would double your filtration. I've found this helps a lot for water quality. I even run up to 3x the filtration on one of my tanks.
 
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