What’s the perfect PH range for aros?

AlbinoSilvers

Feeder Fish
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Jan 4, 2025
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Some say they keep there’s at 8 and I’ve never went above 7 max. Right now my big boys are kept at 6.5. Isn’t 6-7 the ideal range? Me and a buddy are trying to settle an old argument and what’s best FOR THE FISH. What are your Arowanas PH set at usually? 🤔
 
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thiswasgone

Piranha
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Oct 23, 2014
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Some say they keep there’s at 8 and I’ve never went above 7 max. Right now my big boys are kept at 6.5. Isn’t 6-7 the ideal range? Me and a buddy are trying to settle an old argument and what’s best FOR THE FISH. What are your Arowanas PH set at usually? 🤔
As far as I know all freshwater fish, and most saltwater fish, will be able to survive within a 6-8.5 pH range; this includes growing and breeding. However, this doesn't mean it is optimal for them to be in a pH range outside of their native habitat unless they have have been bred for several generations in different conditions; usually this only matters if you have a sensitive wild-caught fish species. Otherwise, chasing a specific pH level is typically pointless as large pH swings will likely cause more damage in the long run. In other words, just keep your pH as stable as possible and usually most non-wild fish will adapt.

For arowana specifically I would assume a semi-stable pH between 6-7 would be ideal considering they live in flood-plain rainforests where oxygen can be scarce. In the past all my arowana (blacks, silvers, jardinis) have been grown and raised to 2ft+ in a pH of 7 with low-to-0 mineral content.
 

AlbinoSilvers

Feeder Fish
MFK Member
Jan 4, 2025
15
3
3
38
As far as I know all freshwater fish, and most saltwater fish, will be able to survive within a 6-8.5 pH range; this includes growing and breeding. However, this doesn't mean it is optimal for them to be in a pH range outside of their native habitat unless they have have been bred for several generations in different conditions; usually this only matters if you have a sensitive wild-caught fish species. Otherwise, chasing a specific pH level is typically pointless as large pH swings will likely cause more damage in the long run. In other words, just keep your pH as stable as possible and usually most non-wild fish will adapt.

For arowana specifically I would assume a semi-stable pH between 6-7 would be ideal considering they live in flood-plain rainforests where oxygen can be scarce. In the past all my arowana (blacks, silvers, jardinis) have been grown and raised to 2ft+ in a pH of 7 with low-to-0 mineral content.
Thank you for the answer! I just got my new test in and my tap/well and tank water comes out 8.0. What’s the safest and more stable way to lower the PH for an Arowana?
 

fishguy1978

Redtail Catfish
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Mar 30, 2020
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I kept mine in 8.2. Would still be in 8.2 if it hadn’t jumped.
 
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fishguy1978

Redtail Catfish
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That is possibly why it jumped.
Arowana are jumpers. It’s who they were created to be. They are known as flying monkey fish in the amazon. I failed to close a lid.
 
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thiswasgone

Piranha
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Oct 23, 2014
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So what’s the safest, most stable and most effective way to decrease your PH for an Arowana?
There are 3 main "safe" and effective methods that can reduce the pH in an aquarium the real question is do you really want to spend money to fill that bottomless pit?

1) As P phreeflow stated you can use RO water mixed with your tap water to reduce the overall pH. The issue here is that your tap water comes out a bit hard which will hasten the degradation of the your RO unit's filter = more new filters = more $ spent. Also RO/DI units should not be used ideally.

2) A cheaper, although questionable alternative depending on where you're at, is storing rain water and using or mixing that with your tap water. Remember to strain your rainwater for any inscet larva or other large solids.

3) Finally you can use many acidic products ranging from, but not limited to, vitamin C to hydrocloric acid in a separate tank and mix that with you tap water to reach your ideal pH level before doing water changes. Always add the acid to the water not water to acid.

All 3 options must be performed every waterchange but 1 & 3 will cost a hefty sum of money overall while option 2 is a dice roll. However, all 3 options will require additional labor and effort on your part. If you're still willing to go through with all of this effort to chase pH then option 1 is the easiest, on demand option. Option 3 may be the cheapest option depending on how large your tank is and what acid you use. Option 2 is the cheapest option and potentially the best depending on your locality but you will also probably have a lot more mosquitoes around...

Finally, I would again suggest not chasing around your pH and just keep using your tap water. The only time I suggest increasing/decreasing pH is when values are above/below 6/8.5 respectively. This is because nitrate/ammonia respectively start becoming toxic at those levels.
 
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