Yellow Tangs keep dying

[Goog]

Yellow Tangs keep dying
I have a 180 gal fish only aquarium that has been setup for about 5 months. Our fish include 2 chromis, 1 banggai cardinal, 1 stars and stripes puffer, 1 queen angelfish (juvenile), 1 powder blue tang, and 1 coral beauty. All added slowly over 5 mos. We have tried to add a (single) yellow tang but they both have died within 7 days of addition. My system was setup and maintained by a very knowlegble local fish guy. I do the weekly maintenance and he visits every two weeks (cleaning/ 20% partial water changes (last saturday before the second tang was added)). Both yellow tangs were hardy when obtained (eating, plump, and active) 2 different LFS. My fish guy QT'd the second tang for 10 days and it was perfectly healthy when added. The there was some territory issues between the coral beauty and both yellow tangs. Neither Yellow seemed intimadated by the coral beauty though. Both tangs were perfectly normal eating/active the night before their death and the next morning each was found on the tank bottom gasping. One was placed in a hospital tank the second could not be retrieved. Both died within hours. No real signs of trauma (no frayed fins). Water parameters Sg 1.017, Ph 8.2, Akalinity 4.0, Nitrites 0, Nitrates 5 mg/l, amonnia 0., T 80.7F.

Is the elevated Nitrate level the result of the dead Tang? I plan on a 20% partial water change tommorow. My fish guy thinks the Coral Beauty is the source of the problem and the Tangs are dying from physical trauma/stress. When a fish dies from a failed acclimation would it normally get sick, waste then die slowly versus as in this case perfectly normal then sudden death? We plan on removing the coral beauty before adding another yellow tang.

Any help would be appreciated. Thx.

 

[Copepod]

Your spg is way too low....it should be up at least 1.024...I have mine at 1.026. I don't think your nitrates are too high. Gasping for air usually is from poor water quality...low oxygen. What type of equipment are you using and what/how much are you feeding them? I can't help with the Coral Beauty, but am sure someone on this forum has tons of experience with them..sure they will be along to help.

 

[Kurt_Nelson]

I'd also wonder about acclimation technique, because as copepod mentioned 1.017 is pretty low... even for just a FOWLR tank. Seems like most FOWLRs run in the 1.020-1.023 range at the low end. Reef tanks run closer to 1.025. It's not like fish can't live in 1.017 water, but the existing fish have had some time to get used to it. The new guy (no matter what kind of fish it is) probably has a hard time dealing with the low SG. Just thinking out loud.

You might as your fish guy about the SG, although I have a feeling they think it's "just fine" since they're the ones maintaining it.

 

[Innovator]

I agree about salinity. Natural salinity (average) occurs at about 35ppt or 1.026/1.027. 30ppt, 1.023/1.024, is the lowest I would venture. My guess is questioning your acclimation procedure and constant aggression from the angelfish or even each other overnight. How did you acclimate and what was the lfs' salinity? If low oxygen was involved the tang would be at the surface so more than likely it was just stressed. As for qt, if you do not sustain at least a 30 day time-frame then it is rather pointless.

 

[melosu58]

All good advice above. Also what size is the yellow tang. If it was me and I had the size tank you do if aggression is the problem then I would add a large yellow tang. You might have already but just a suggestion.

 

[Goog]

My fish guy reccommends low sg (1.017-1.020). I just checked it and its 1.018ish. He quotes Fenner (The concientous Marine Aquarist) that low sg reduces parasites and o2 content is enhanced. Sure enough thats what fenner says p. 104. They run low sg at the LFS where he works for that reason. The two tangs were smallish 3" or so. Fenner also says to avoid Yts less then 3". I appreciate everybodys comments, please keep the advice comming. How do you convert Nitrates 5 mg/liter to ppm? I thought 5mg/liter was high?

Thanks again!

 

[Goog]

BTW,

I hired my fish guy to teach me the ropes. I'm in the process of taking over the care of my tank/fish. I've read/studied Fenner plus other books and lurked on a lot of forums. All advice is greatly appreciated. There's no substitute for experience.

Thanks again!

 

[melosu58]

I agree about salinity. Natural salinity (average) occurs at about 35ppt or 1.026/1.027. 30ppt, 1.023/1.024, is the lowest I would venture.

I thought James said it best. There are some things that me and Mr Fenner dont agree on. Why would a lower salinity be better than what nature has already. That`s OK for the LFS as he wont have the fish long anyway but you will. My advice and my experience is that it`s too low. My yellow tang is 10 and a half yrs old and always been in 1.025 salinity. Experience is a wonderful thing.

 

[Ziggy953]

I agree with the others. Lower SG is ok in a QT tank or in a LFS but for your main tank it should be closer to what nature is. I have a reef tank and keep it at 1.026. Yellow tangs are usually pretty hardy fish so I'm leaning towards poor stock or acclimation issues. Raise the SG of your tank gradually.

 

[ryshark]

What are you using to measure SG? If it is one of those swing arm hydrometers you are probably off. It may even be 1.014 if using one of those. If you are using a well calibrated refractometer then your reading is good. Nitrate of 5 is perfectly fine. I don't know about fowlr, but with a reef tank the Alkalinity DKH of 4 is way too low, should be closer to 7 or 8 on the low end. Again that is for a reef tank with coral, im not sure how the fish react to low dkh. If you do plan on bringing the SG up do it slowly as Ziggy mentioned... bring it up by about .001 per day. Bringing it up is more stressful on the fish than lowering it.
Also, what were you feeding those yellow tangs before they died?

 

[Innovator]

If I am not mistaken Mr. Fenner recanted his thoughts on lower sg and revised the statement in his newer edition. The reason lfs' use a lower sg is to save on salt (less money spent) and, in theory, reduce parasite %'s; however, unless they are using a hyposaline concentration then the parasite (Cryptocaryon/ich) can still live and reproduce. As far as the Alkalinity reading, am I wrong is assuming 4.0 is in meq/l? If so then that is fine since I do not see 4dKH as possible without having a bad batch of salt.

 

[ryshark]

Good point about the alkalinity... I got to remember there are so many ways to measure the same thing.

 

[Goog]

Thanks guys.....some very valid points i.e. the best long term results would be obtained by creating an environment as close as possible to nature. Point taken. Yes measured with a calibrated refractometer. We had 1.018 prior to water change (20%) and brought it up to 1.019 post. Do you see any problem raising it .001 per water change (every two weeks)?

Speaking of water does everybody use RO/DI water?

Thanks...keep the advice comming!

 

[melosu58]

Speaking of water does everybody use RO/DI water?

I know I do. What are you using? Also you dont have to wait till PWC`s to increase salinity. You can also add SW instead of FW during your top offs. that will raise your salinity. Maybe add a few gallons of SW every three days. I believe you said you have a 180 gallon tank.