Low SG, is this killing my fish?

[Kevp99]

Hi, I have a 270 litre tank it's been up and running for about 7-8 months (this is my first SW tank). I recently noticed my SG is really low it's about 0.015 how do I bring this back to normal, I have been trying to keep it between 0.023 and 0.026 is that correct? Also my yellow tang is swimming/ lying at the bottom of the tank, yesterday she was swimming ok and feeding, she hasn't eaten anything today, she also looks like she has a red belly on both sides! Is this due to the SG being low? All othe water checks are fine I think! 0 ammonia 0 nitrite 20 nitrate ( I have problems keeping nitrates lower than 20) havent checked Ph will do tomorrow. Any help would be much appreciated! Thank you kev

[Reefing Madness]

You'll have to take a few days bringing up that SG. Lowest point should not go under 1.017. Red on the Tang is a really bad sign. Your fish are stressed to the max. Your SG is to low, and you have Nitrites in the water as well.put the 2 together and this may be your cause of fish issues. SG in a fish only tank can range from 1.017-1.026.
You might want to do a big water change, like 50% at this point. One to knock down those trites some, and maybe bring that SG into the good range. Maybe try and bring it up to at least 1.018-1.019 range.
Oh, forgot. Your Nitrates are fine for a fish only tank, if you can keep them under 40, you'll not put the fish under stress.

[Kevp99]

Thanks, had a look in the tank this morning and my yellow tang looked bad, hopefully she will pull through as she is a beautiful fish! I checked my nitrites and they are all ok reading was 0, so was my ammonia! The only thing I can see that is wrong is the SG level!! Could anything else have stressed my tang? These are the fish i have: regal tang only 2inch max, emperor cardinal 3inch, clown 2inch, a small damsel and 3 red stripe cardinals. I dont think she was bullied by them, wat you think? I can't make to lfs until Friday which I think is going to be to late! Will try and get there tonight and do a water change!! Will let you know how I get on!! Regards

[Reefing Madness]

Well, no, the low SG alone will not kill the fish. When in QT you can put them into Hypo, and that SG is at 1.009. So, at this point I would not be able to fathom a guess. If your water parameters are in check. Only other thing I can throw out there is, what have you been feeding the fish, and has he been eating?

[Kevp99]

Just got home from work and found my tang dead!! Well annoyed!! I managed to get to lfs and get pre mixed salt water, added about 20L as it was only 1.019! Going to see if that makes a difference, then add a little more tomorrow maybe, I have mixed some more salt into the remaining 25L just to bring it up a little more. Keep you updated!

[Kevp99]

I was feeding them some frozen food mixed with garlic, flake and nori! She never really went for the nori but the garlic and flake she eat!! I saw some where that it be some thing to do with electricity, my heater?? Any thoughts on that?? Thanks for your help, trying to upload a pic of the tang but cant seem to do on iphone! She had a really red belly if that helps!!

[Reefing Madness]

Yea, stray current will kill the fish. Gotta have a volt meter to test this though. Try feeding Mysis Shrimp, Romaine Lettuce for the Tangs. Try and stay away from Flake food as this isn't very good for them.