Is a .002 salinity change enough to kill fish?

[Chaz88]

Yesterday I did a 25% water change and dropped the salinity from 1.024 to 1.022. That is the only significant water parameter difference from before the water change. Today I woke up to 5 dead fish. 2 clowns, 2 Firefish and 1 Royal Gramma. They were all active and eating showing no sines of stress before the water change. The blue Mandarin and the Orange Spotted Goby seam just as happy and active as before. The tank is a 120g and all the fish are / were 2" or under. I still have some mild cycling going on from slowly adding more live rock. The only other change I made to the set up was to add more bio media to the filter. After more than 30 years of keeping freshwater fish and having no significant losses in many years this saltwater tank is making me feel like I just started learning all over again.

 

[mgk]

short answer no.

long answer: noooooooooooooooooooooooooo. fish are easily fine with in 1.018-1.026. given time to adapt they can even go outside of those ranges.

 

[Chaz88]

Any idea what I could have done wrong, with a water change, that would have killed the fish mentioned and left the others just fine?
I dechlorinated the water, matched tempter and checked salinity in buckets before adding it to the tank. I am kind of at a loss to identify what I did wrong.

 

[mgk]

I still have some mild cycling going on from slowly adding more live rock

what does this mean(what do you mean by mild cycling)?

 

[Otto_VonBacon]

What are the other basic parameters? (ammonia, nitrite, nitrate, pH)

 

[Chaz88]

When adding more live rock I get a small jump in ammonia and nitrite form 0 to a max of .5. It goes back down in a day or two. I was told this is normal to have a "small cycle" when add more live rock. Is that incorrect? I was doing the water change, mostly to keep this in check. The fish were acting fine with the levels but any reading on those two test I consider bad when fish are in the tank.

Daily checks have had the readings as follows, except when I added more rock. Nitrate 0-20, Nitrite 0, Alkalinity 180, pH 7.8-8.4, Ammonia 0.

I am going to pick up a new master test kit tomorrow and see if I get different and more accurate readings. I have my freshwater tanks stable enough that the strips work for a quick check but I am thinking maybe they aren't cutting it for my saltwater tank. Still seams like a water change should have improved anything that was going undetected.

 

[mgk]

When adding more live rock I get a small jump in ammonia and nitrite form 0 to a max of .5. It goes back down in a day or two. I was told this is normal to have a "small cycle" when add more live rock. Is that incorrect? I was doing the water change, mostly to keep this in check. The fish were acting fine with the levels but any reading on those two test I consider bad when fish are in the tank.

Daily checks have had the readings as follows, except when I added more rock. Nitrate 0-20, Nitrite 0, Alkalinity 180, pH 7.8-8.4, Ammonia 0.

I am going to pick up a new master test kit tomorrow and see if I get different and more accurate readings. I have my freshwater tanks stable enough that the strips work for a quick check but I am thinking maybe they aren't cutting it for my saltwater tank. Still seams like a water change should have improved anything that was going undetected.

are you sure the strips work in saltwater?

It is normal to get a ammonia spike with the live rock, but its still not healthy for the fish.

 

[Chaz88]

are you sure the strips work in saltwater?

The label says they are good for fresh and salt. They also have a comparison chart for each. I just bought them, so they should not be out of date. They are the Jungle brand. I will spring for the master saltwater kit. As much as I have spent on the set up there is not much reason to be thrifty with the test kit. The strips are just more convenient and quicker to use.

 

[sikoko]

were you doing a water change or adding becuase of evaporation?

 

[Kevin8888]

Is it possible there was a temperature shock from you waterchange? As if you added 25% water that was cold it would likely cause a huge temp drop. I also agree any ammonia is bad for fish, but... like you said they should tollerater small ammounts. Have you inspected the remains for parasites? As live rock can easily add things that could kill your fish.