Can raising the salinity too fast kill fish and leave the coral fine?

[flatlander93]

I have a newish tank that has been fully cycled for about 6 weeks. I have been checking the salinity with a Refractometer and using di water to calibrate. Recently got some actual calibration fluid and was way off. Like 1.021. I stopped topping off and it raised to 1.023-4 in a day. Fish all died. I’m assuming this was the problem. Coral is thriving. Just wanna double check before I add new fish. Thanks.

 

[Shawaiz_106]

Going from 1.021 to 1.023-4 in a day might stress them out but shouldn't kill all fish. Can you post water parameters any symptoms of the fish ?

 

[Reeflix]

did you recently add in a fish? it could be some disease. also could there have been an ammonia spike? there are a lot of variables. i mean maybe one or two super sensitive fish might die from that, but i dont think so

 

[homer1475]

Your corals would react to the salinity changes long before your fish would. That small of a salinity change would not kill a healthy fish.

 

[Reeflix]

yeah definitely. was something else

 

[Spare time]

I'm betting issues with disease or oxygen (oxygen especially if they died at night) since I can't imagine that salinity change to do anything.

 

[flatlander93]

I had been dealing with a bacterial bloom that has lasted a couple weeks. Could that have been the culprit? It was a pair of clownfish and a watchman goby. Nitrate was at around 10. Temp around 79.

 

[flatlander93]

Ironically, it was the morning I went to get my UV sterile which has since made the tank perfectly clear. Frustrating.

 

[brandon429]

Jay in the fish forum directly said this level of salinity jump can kill/harm fish, I wouldn't expect to get that answer outside the fish-specific forum as nearly all reefers here in the general forum don't use any type of salinity acclimation, owing to this thread, so they're not likely to believe your salt jump could harm:

I stopped equalising water for fish.

Just a reminder,my thread is about acclimatising fish and what I do or don't do, inverts are a totally different matter.

www.reef2reef.com

I don't believe anything but the salinity jump killed the fish. curing a bloom isn't lethal, the cause and effect was directly on the same day to a known cause/killer

 

[Reeflix]

i dont either, but who knows

 

[flatlander93]

So I guess it’s at least plausible that either the salinity or the oxygen was probably the culprit. I just don’t want the tank to sit too long without fish.