Can a sudden change in salinity kill fish?

glb · Mar 1, 2015

I got two clownfish yesterday that didn't make it through the the night. Tank info 12g nano, 5 years old but recently broken down after a tank crash. Salinity in tank is 1.025. Should I lower it to 1.021 and see if that helps? All my other numbers are perfect.

glb · Mar 1, 2015

Tank isn't cycling btw.

Reefing Madness · Mar 1, 2015

No, it would have to be a big jump in order to kill the fish. If you just got them, they just didn't acclimate, it happens.

-Logzor · Mar 1, 2015

An ammonia spike may have killed your fish, in all likely hood, not poor acclimation or differing salinity. Did you test your ammonia or nitrates before you added the fish?

TJ's Reef · Mar 1, 2015

If your tank is currently at 1.025 S.G. and the Fish came from 1.017-19 which is not overly uncommon for LFS's then YES a sudden upward change without hours long acclimation certainly could explain their deaths.

Cheers, Todd

glb · Mar 1, 2015

-Logzor said:
An ammonia spike may have killed your fish, in all likely hood, not poor acclimation or differing salinity. Did you test your ammonia or nitrates before you added the fish?

I did test before and ammonia, nitrites were zero, nitrates 5ppm. I tested ammonia again this morning and it was zero. I just realized I cleaned the sponges in fresh water yesterday after the testing because they were filthy. Stupid noob mistake but they were filthy. I'll bet the spike happened overnight but since it's an established tank, the ammonia was gone by this morning.

glb · Mar 1, 2015

TJ's Reef said:
If your tank is currently at 1.025 S.G. and the Fish came from 1.017-19 which is not overly uncommon for LFS's then YES a sudden upward change without hours long acclimation certainly could explain their deaths.

Cheers, Todd

So I guess I should get the salinity down to 1.021, which is easy because my salt mix SG is that. I'll just take out some salt water and replace with RO until I have it down. The tank is 5 years old and was stable for a long time until it crashed after an AC outage last summer that heated it to 92 degrees. It was never the same after that.

TJ's Reef · Mar 1, 2015

IMHO/IME Fish and certainly Corals do much better in the higher S.G. range of 1.024 --> 1.026. LFS's use the lower range for two primary reasons only: CHEAPER and a myth that the lower salinity will deter Ich from taking over their systems. So, for future Fish and especially Shrimp ask what and/or measure the LFS's S.G. first and acclimate accordingly. Anything over .003 should take some time in acclimation/drip method.

Cheers, Todd

glb · Mar 1, 2015

Just called the LFS and the fish are kept at 1.022, which isn't that bad. I think I killed them by the way I cleaned the sponges. I feel terrible. My LFS is the best and will give me a break to replace them even tho it was my fault because I'm a repeat customer. That's rare!!

glb · Mar 1, 2015

TJ's Reef said:
IMHO/IME Fish and certainly Corals do much better in the higher S.G. range of 1.024 --> 1.026. LFS's use the lower range for two primary reasons only: CHEAPER and a myth that the lower salinity will deter Ich from taking over their systems. So, for future Fish and especially Shrimp ask what and/or measure the LFS's S.G. first and acclimate accordingly. Anything over .003 should take some time in acclimation/drip method.

Cheers, Todd

So you think 1.024 is better?

glb · Mar 1, 2015

Maybe I should switch salt mixes. IO Reef Crystals is 1.021.

acroaddict · Mar 1, 2015

glb said:
Maybe I should switch salt mixes. IO Reef Crystals is 1.021.

IO Reef Crystals is 1.021 because of the way you mix it. Just add a little more salt when mixing and you will get higher salinity.

TJ's Reef · Mar 1, 2015

glb said:
So you think 1.024 is better?

Yes, I do and you can just add more salt to make any mix at this range. For std I/O as an example to make 15 gallons I used 8 slightly rounded cups of salt. To make even better for a Reef Tank full of Coral I added a Tablespoon of Tech M Mg supplement and a heaping teaspoon of Kalk (Calcium Hydroxide) which brings it up to near "Reef" salt mix levels for pennies.

Cheers, Todd