Specific gravity question!

[yonsu]

Hi everyone,
I just have a quick question regarding specific gravity. I currently keep my tank at around 1.023. I ventured to PetCo today and purchased a maroon clownfish. Most of their tanks, of course, looked terrible and many of their fish were sick. But the maroon clowns looked healthy and I could not resist. I inquired about the specific gravity of their system, and was astounded when (the manager) informed me that it reads 1.001! I thought for sure that this must have been an error, as I'm under the impression that pure freshwater is 1.000? The manager was actually very rude and basically snuffed my hesitation, stating that I was wrong. I made a remark about how I'm surprised so many fish could have marine ich with such a low specific gravity, and he asserted "well, it is what it is" before walking away. I tested the store's water myself when I got home and did not expect to see that it actually read at the very bottom of my hydrometer (mine only goes down to 1.012). So, I don't understand! Can anyone offer any insight?

 

[DeeSeven]

Hi everyone,
PetCo today and purchased a maroon clownfish. Most of their tanks, of course, looked terrible and many of their fish were sick. But the maroon clowns looked healthy and I could not resist.

:screwy::screwy::screwy::screwy::screwy:


also sounds like petco has no clue what their talking about (which isnt shocking) you should be up around .023-26 give or take

 

[fsn77]

Hopefully, he misspoke and he meant 1.010. Hyposalinity is typically done at a SpG of 1.009. Even with slow acclimation, I'm not so sure there's many marine fish that can survive at a SpG of 1.001.

And, yes, 1.000 is technically the SpG of pure freshwater.

Whatever the SpG really was, I hope that you slowly drip acclimated the clown to your tank. If it was that different from your tank, an acclimation period on the order of hours is really the safest bet.

 

[Wycco]

I'm not an expert on marine fish but that just seems horribly wrong!

I do recall reading once upon a time that Clowns can tolerate very low salinity levels for a while. Doubt it's very healthy for them- especially not when purchasers take them home and try and add them to their tanks.

Idiots at Petco is all I can say. Just because a fish can tolerate something for a while- doesn't mean it should be made to.

 

[Amphiprion]

Though some stores keep levels that low for prophylactic purposes, keeping fish in it continually may (unfortunately, there is evidence on both sides, though I have only seen studies done on diadromous fishes--which is difficult to assess when comparing strictly marine species) cause eventual kidney problems as the fish have to accommodate the extra blood volume due to water influx. There are lower limits, though, and 1.009 is the published specific gravity that is supposed to kill most marine ich strains. The thing I worry about is that by continually keeping their fish in these conditions and with a massive influx of different fish from many sources, that it will eventually select very resistant strains, rendering the relatively safe and very effective hyposalinity treatment practically useless. I recommend against the practice altogether for this reason and the above reasons.

 

[yonsu]

I actually pointed out that typically brackish conditions have a specific gravity of about 1.010, and he told me that I was wrong. So, I don't think he misspoke. Thanks for the responses thus far.