Need some emergency help on acclimating fish

[gabriellar]

Hi I got a longnose yellow butterfly fish from a LFS and surprisingly found out they kept the butterfly fish at 1.015 salinity after I tested the water. My tank is at 1.026. I have slowly acclimated the water in the past hour for 0.003 and this fish starting to show sign of stress by shaking his head hard. What is the quickest way to get it acclimated to my tank to minimize the potential harm to this fish? I still have 0.008 increment to go.

 

[keagan]

What did you test the salinity with? Was it recently calibrated?

 

[gabriellar]

I have a refactometer that I test my water on a daily basis, the reading is the same as the water test I got back from LFS

 

[KrisReef]

Hey, READ THIS:

Post in thread 'Newly Purchased Fish dying within 24-hrs in my QT'

Jun 28, 2026

Sorry, I forgot to mention I floated the bag for 30 minutes first. The salinity was matched, at exactly the same value (by probably pure luck).

If the meter is off, wouldn’t it be off the same for both readings? So even if off, if it’s matched, it would still be matched right?

The biggest issue with acclimation is when a dealer holds fish at a lower salinity than your tank - even with careful acclimation, you should keep the rise at less than 3 SG points (1.020 to 1.023 for example). Sounds like that wasn't an issue. Fish that are shipped have high ammonia in the water, and...

• Jay Hemdal

• 

 

[gabriellar]

Hey, READ THIS:

Post in thread 'Newly Purchased Fish dying within 24-hrs in my QT'

Jun 28, 2026

Sorry, I forgot to mention I floated the bag for 30 minutes first. The salinity was matched, at exactly the same value (by probably pure luck).

If the meter is off, wouldn’t it be off the same for both readings? So even if off, if it’s matched, it would still be matched right?

The biggest issue with acclimation is when a dealer holds fish at a lower salinity than your tank - even with careful acclimation, you should keep the rise at less than 3 SG points (1.020 to 1.023 for example). Sounds like that wasn't an issue. Fish that are shipped have high ammonia in the water, and...

• Jay Hemdal

• 

Thank you Krisreef, this is helpful. Looks like the max safe salinity swing is 0.003. I don't see this doc mention how frequent the salinity can swing for this much, I assume 0.003 per hour is safe?

 

[KrisReef]

Thank you Krisreef, this is helpful. Looks like the max safe salinity swing is 0.003. I don't see this doc mention how frequent the salinity can swing for this much, I assume 0.003 per hour is safe?

@Jay Hemdal, I don't recall the timing between steps, for raising salinity?

 

[Jay Hemdal Verified Community Expert]

Hi I got a longnose yellow butterfly fish from a LFS and surprisingly found out they kept the butterfly fish at 1.015 salinity after I tested the water. My tank is at 1.026. I have slowly acclimated the water in the past hour for 0.003 and this fish starting to show sign of stress by shaking his head hard. What is the quickest way to get it acclimated to my tank to minimize the potential harm to this fish? I still have 0.008 increment to go.

That’s really too much of a rise to handle in one acclimation event - it can take 24 to 48 hours to safely bring a fish up in salinity that far.

You’re kind of stuck though - you can bucket acclimate it with an air stone and give it multiple water additions over six hours or longer.

 

[KrisReef]

I think that lowering your DT and then raising it slowly might be easier to manage instead of messing with the bucket of fish?

 

[gabriellar]

Okay I'll try both. Thanks guys!

 

[EricR]

Okay I'll try both. Thanks guys!

Timeout!
You're not thinking of lowering your main tank with livestock (corals and other inverts?) salinity down to meet in the middle, are you?
*I'm assuming you have corals/inverts just based on glancing at other posts you've made

 

[Jay Hemdal Verified Community Expert]

I think that lowering your DT and then raising it slowly might be easier to manage instead of messing with the bucket of fish?

Yes - it is, except in most cases, when people are running 1.026, it means there are invertebrates in the tank and you shouldn't lower the specific gravity if that is the case.....but you're correct, maybe I shouldn't have just assumed that the OP had invertebrates....

 

[W31Olds]

I would use a bucket or a 18 gallon plastic tote or a cheap 10 gallon Tank (best). Throw in a heater and an airstone or sponge filter and do it that way. You will probably need these items for future Fish purchases anyway. Stepping up from 1.015 to 1.026SG really needs to be done over extended acclimation.

 

[gabriellar]

Thank you guys so much! Yes I have invertebrates in the tank — snails, emerald crabs, hermit crabs and sexy shrimp, along with other corals. Lucky that I lowered my tank down to 1.025 and stopped there cuz I was mainly adopt the bucket + air stone method.

So far the fish had his dinner and breakfast. And acclimated in the bucket to 1.020! I put some carbon pieces into the bucket as well and am changing 50% of the water every time after feeding. Hope this method is fine.

Update picture for fish:

 

[EricR]

I think that small amount of water is the main concern.
Not much space for the fish (stressful) and not sure how fast ammonia might be a concern.
Maybe frequent 50% water changes are sufficient.

Personally, I'd much prefer an idea like stated in post# 12.
If you have a local Petco, they're having 50% sale right now so you could get a 10 gallon tank for $18.
Cheapie heaters can usually be found <$10 and looks like you already have airstones so that's good.
I'd shoot for a week or more to bring up salinity to normal but listen to others here for how quickly is safe as I've never had to deal with that before.
*you're obviously not medicating so any spare rock from sump or tank would help with ammonia processing and hopefully a couple of airstones create enough flow (maybe)

Good luck!

 

[KrisReef]

Yes - it is, except in most cases, when people are running 1.026, it means there are invertebrates in the tank and you shouldn't lower the specific gravity if that is the case.....but you're correct, maybe I shouldn't have just assumed that the OP had invertebrates....

I was thinking it was fish only....( but with a second look at old posts I was wrong about that.)

 

[gabriellar]

I think that small amount of water is the main concern.
Not much space for the fish (stressful) and not sure how fast ammonia might be a concern.
Maybe frequent 50% water changes are sufficient.

That’s a good point. I’m putting a amonia alert in it for now, and will set up the 10 gallon soon.

 

[gabriellar]

I was thinking it was fish only....( but with a second look at old posts I was wrong about that.)

Sorry I should’ve put more thorough info in the first place, wasn’t aware invertebrate is the main factor to consider for salinity change learned something new about reef tank again!

 

[KrisReef]

Sorry I should’ve put more thorough info in the first place, wasn’t aware invertebrate is the main factor to consider for salinity change learned something new about reef tank again!

The reef tends to have stable water parameters except in shallow coastal areas where rivers or city runoff may input rain and other freshwater. These areas have lower quality coral and fish populations (imo) and usually have more algae from the nutrient inputs. Fish and coral can handle some changes, but as Jay says the degree and direction are important for survival and recovery.

 

[winxp_man]

I know the SG LFS’s near me are at. But online retailers are hard to say. I now ask all places before purchasing so I don’t run into this issue. Even LFS’s. Only reason the do this is to save on salt and hide disease issues.

It’s all about the Benjamin’s these days sadly!