Arowana Stopped Eating After Large Water Change

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Fire Eel
MFK Member
Oct 11, 2008
1,895
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Malaysia
Two weeks ago, I bought a High Back Gold arowana around 11~12" and added her into my tank which has a flowerhorn.. Surprisingly, both fish got along well without even a slight scuffle..
The arowana was eating well until two days ago when I saw that my flowerhorn was sick again so I moved him to the hospital tank.. I changed around 80% water hoping that would prevent any further outbreak of whatever that infected him (the fh had pop eyes prior to this but recovered and now the disease came back)
My usual water change routine is 50% weekly with 1 tablespoon of aquarium salt for every five gallons of water changed..
When the water was drained to almost 80%, the aro started rubbing against the glass and she continued to do that until I filled the tank with water..
After an hour or so, I tried feeding the aro superworms and she ate.. Then later that night, when I put in the worms, the aro just let them sink to the bottom(they were still there the next morning).. Yesterday, the same thing happened..
The aro is also occasionally rubbing against the glass and swims at the bottom more frequently than before (during the first two weeks, the aro just swam around the surface and rarely swam to the bottom.. at most, she would dive down to grab any worms that were sinking)
I really don't know what is going on.. I don't have a test kit so without knowing the water parameters, can anyone tell me what could be wrong?
I've a theory that maybe I added too much salt at once? But I'm just replacing the salted water that I siphoned out with new salt..
 

xharold

Feeder Fish
MFK Member
May 16, 2014
25
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Scarborough
You shocked the fish by doing so much water change. My maximum for doing watcher changes is 50% so that when the water fills up the arowana won't be stressed out. Give it a couple of days for him to acclimate again and try bringing your water to your LFS and ask them if they do water testing.
 
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StingraySteve

Gambusia
MFK Member
Mar 20, 2013
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Changing 50% each week is a bit much. In most established tanks 15-25% weekly is sufficient. Ur tank may have restarted the cycling process. Not too sure how u can reverse those effects but might want to check your ammonia and nitrates just to be sure
 

xraycer

Arapaima
MFK Member
Sep 5, 2013
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Southern NH USA
I do a 50% w/c, every four days, to all my tanks and the all the fish are active and eating fiercely within an hour afterward.

Why do you feel you need to add salt at all?

80% water change is a huge water change, so temperature differences could be a major issue. But, I did notice that you're from Malaysia so the tap water is probably fairly close in temp range to tank water. Do you check the temp changes during w/c?

The aro could of also possibly picked up some infection possibly from the FH or from stressed out from large w/c.
 

noelsfishland

Jack Dempsey
MFK Member
Jun 2, 2013
422
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In My Aquarium
Maybe you threw of your Bio in the tank with the heavy water change,It might be high in nitrite and ammonia you really need to check your water quality.In the meantime I would put some prime in to treat poor water quality or try Seachem Safe. It is cheaper than prime and has the same formula only in powder form and more concentrated.I would do another water change 50% get out what ever bad stuff you have in tank and keep the salt formula you have been using.
 

MichaelE

Feeder Fish
MFK Member
Dec 27, 2005
94
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sweden
Changing 50% each week is a bit much. In most established tanks 15-25% weekly is sufficient. Ur tank may have restarted the cycling process. Not too sure how u can reverse those effects but might want to check your ammonia and nitrates just to be sure
I do a 70-75% WC every week in my predatory tanks, it has worked fine for about 10 years so I don't know about that.
Sometimes fish just won't eat for a while, it should be fine.


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StingraySteve

Gambusia
MFK Member
Mar 20, 2013
545
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Australia
I do a 70-75% WC every week in my predatory tanks, it has worked fine for about 10 years so I don't know about that.
Sometimes fish just won't eat for a while, it should be fine.


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Wow that's a massive amount. Where I am the tap water is often treated with chloramine. If I changed my water like u, I would have killed my fish within a month. I understand predatory tanks do have very high bio loads but I cringe at that amount.

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theskibag

Plecostomus
MFK Member
Mar 23, 2011
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Galway, Ireland
I do the same, around 75% every week but treat the water and heat it to the same temp as the tank before it goes in. Have never had a problem
 

MichaelE

Feeder Fish
MFK Member
Dec 27, 2005
94
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sweden
Wow that's a massive amount. Where I am the tap water is often treated with chloramine. If I changed my water like u, I would have killed my fish within a month. I understand predatory tanks do have very high bio loads but I cringe at that amount.

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That may be the difference, here in Sweden the water isn't really treated with a bunch if chloride.


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jechrz

Gambusia
MFK Member
Nov 5, 2013
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Canada
i think feeding your aro too much can cause loss of appetite. i myself do 50-60% h2o change weekly and my rtg aro is still crazy for food. i use to feed mine daily and seen this loss of appetite occur. what i did was stop feeding for 3 days and change my feeding sched to once a day every other day. fish will eat when hungry so patience is also key here, imo.

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