Near Death Experience and Hospital Setup

TXMike

New member
I recently found my favorite fish, a powder blue tang, laying at the bottom of my tank obviously near death. I scrambled around testing the water and concluded I had let the salinity get too high from evaporation. (Normally around 1.025, now slightly above 1.027.) I found no other parameters out of normal.

Even if this wasn't the ultimate cause of death (he finally did a few hours later,) it raised questions as to what I could do if I find a near-death fish again. Here are my 2 questions...

1. What are all the possibilities...what can I do with a near-death fish that gives the best chances of survival?

2. If I do decide to move him into a seperate "hospital tank" should the parameters be any different than the show tank? I have heard fish prefer a lower salinity closer to 1.020....but would the shock of the salinity change do more harm than good?

Any help is much appreciated!
 

Amphiprion

Premium Member
I doubt the raised salinity was the problem, but what are you using to measure the salinity?. Fish are more than tolerant of higher levels. As far as preference goes, that is debatable. There is no real evidence to suggest that fish should be kept in consistently low salinity water. However, in the ocean, fish are able to change both the salinity and temperature they swim in by moving into different areas. Some fish prefer different temps and salinities throughout the day--so you can see where I am going with this. I see no good reason to keep salinity below natural seawater levels (i.e. 1.026-1.027, with some slight variation being just fine). I would not try to move it at this point, as the sudden change may "push it over the edge." I would do a good water change with aged, aerated seawater. IME, leaving them be may be the best chance. Also, try opening some windows in the house for air movement and adding an airstone or extra aeration of some sort to the tank. Lastly,
 

Black Mammoth

Premium Member
How long have you had your powder blue tang? Did it have Ich? Not to be the tang police, but 55g is too small for a PBT. Maybe he got stressed out.
 

TXMike

New member
I have had this tang for a couple of months. He did not show any signs of ich, and the rest of the fish appear normal. I know the tank was a bit small, but so was he...about 4" nose to tail. But you're right, that might have been it.
 

Reefy

Premium Member
If he was eating well and not showing any signs of disease, I would suspect a PH drop. What was your PH?
 

TXMike

New member
The latest "Quick Dip Test Strip" (I can hear the shrieking already) says:
Nitrates @ 40ppm - Nitrites @ 1.0ppm - Alk @ 300ppm - Ph @ 7.8
 

TWallace

New member
pH seems a bit low. I too doubt that the SG being at 1.027 is what caused it. Normal SG on reefs is 1.026, right? Maybe it was a combination of pH, SG, nitrites and the somewhat small tank for that species?
 

McCrary

Can't Stop Time
Sorry to hear about your fish. The death was probably caused by more than one issue. If you see another fish that is in distress try to put it in a tank that can be treated and with a slightly lower salinity. I have kept fish in tanks that had a salinity of 1.015 when they seemed ill.
 

reefshadow

New member
any detectable nitrite is cause for concern. if you have nitrite, then you had detectable ammonia in the very recent past. sounds like you had a cycle for some reason. i would bet that this coupled with the lowered ph did your fish in.

sorry about your fish.
 

reverendmaynard

New member
Low PH at that alk would indicate a lack of proper gas exchange, or elevated CO2 levels in the room, unless you are running a calcium reactor. I would try to raise it.

Of course, using a test strip to measure PH is not the best way to go. Perhaps a fellow reefer can loan you a PH meter?

Some experiments to do:

Take a cup of tank water and aerate with an airstone for 1/2 hour in the tank room. If it rises, that would indicate poor gas exchange in the tank. If it doesn't...

Perform the same test using outside air. This should certainly raise the PH to 8.2 or higher. If it does raise it, you need to try to pull fresh outside air into the tank room. People have built ductwork from the outside to their skimmer intake for this purpose. If it doesn't rise, you're probably looking at a bad test kit.

If you are running a calcimu reactor, consider reducing it's output and supplementing with kalk to keep the PH up.
 

LegoZ81

New member
Aren't PB tangs somewhat more sensitive 'trAtes than other tangs?
Also agree if there was a spike in ammonia it could have damaged the tangs gills then the bacteria ramped up in population to eat it and then could have dropped the O2 concentration slightly and in normal respiration producing co2, dropping ALK and pH (problem in freshwater ponds, wet-dry biological filtration used alk due to the co2 produced by the bacteria)
so IF there was a cycle:
Ammonia damaged gills and stressed fish.
NitrIte should not have harmed the SALTWATER fish from what I have read, salt is used it freshwater to protect fish from NitrItes damage (but it is a signal here)
Stress due from highish NitrAtess.
rapid pH drop when alk dropped to a level it could no longer support 8.0+
 

Amphiprion

Premium Member
I doubt it was the nitrites or nitrates. Even powder blue tangs can tolerate nitrate concentrations higher than that. BTW, if there were enough salt to prevent nitrite poisoning in freshwater fish, it would have to be more like a (more saline) brackish tank, which the fish would not like very much.
 

reefshadow

New member
My point is that if there were DETECTABLE nitrItes, there was obviously in the very recent past an elevated ammonia reading. A well established tank should never have detectable ammonia or nitrites unless something is producing more food than the current bacterial population can handle.

A mini cycle would also have driven down the alk/ph, leading probably to lower o2 as stated, and stressing the fish to death.

And yup, pbt's (like most tangs) are very sensitive fish, especially to lowered ph and o2, since they are adapted to water at near saturation of o2, and high stable ph.

Sorry about your fish :(
 

vanmo92

New member
I would say a nitrate of under 15 is OK for fish but not 40. THey can survive high nitrates as i learned when mine were 180 PPM and my fish were still living but definetly try to keep them under 15. also nitrite should be undetectable. And i would try to get the ph up to arround 8.1-8.3
 
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