Naso Tang fast breathing


New member
I have had a pretty large (10" +) for about six months or so. This morning he seemed fine, but this afternoon is is at the bottom of the tank (not on his side) and breathing heavy. He looks a bit pale and did not join in at feeding time. All of the other fish seem absolutely fine. He doesn't look like he has been picked on and in fact is the king of the tank. I will try to get a pic if it will help, but he is usually behind the rockwork. Thanks for your help.



New member
A large range of possibilities exist when there is the only one symptom of fast breathing. It ranges from the onset of disease, poisoning, and dwindling health to something as simple as old age.

The obvious (and somewhat useless) answer is that it is under (one or more) stress. Trying to discover the source of it/them and eliminating or minimizing it/them is your goal. If the fish was nutritionally fed well and healthy before this symptom, then the fish can live a few weeks without eating. But if this is the onset of a disease, the fish might not have that long to fight it.

A photo would be best. Look closely at the fish; all over the fish as best you can for any signs of something wrong or different.

Provide additional information if you care to:
How old is your tank? When did it originally cycle?
What kind of system do you have (tank volume, dimensions, bio-filtration method, the equipment you use, any carbon or other chemical filtration, kind of substrate, etc.).
List all specimens & sizes in the tank (fish, inverts, corals, clams, snails, crabs, shrimp, etc.).
If you have a refugium and/or sump, what is living in it?
Do you use a quarantine tank and procedure? Did the fish have any problems or disease when you first got it? Any disease since?
Foods you use and feeding schedules.
Do you use any vitamins? Fat additives? Any elemental or other additives? Please list all.
Chemistries ââ"šÂ¬Ã¢â‚¬Å“ please give actual numbers (Ammonia, Nitrite, Nitrate, Phosphate, Silica, Ca, Alk., and any others you have)
Water parameters ââ"šÂ¬Ã¢â‚¬Å“ please give actual numbers (pH and your pH range, salinity or sp. gr. & range, temperature range)
Do you see any of the following in your system: hair algae; micro algae; cyanobacteria growths; dinoflagellate (zooxanthellae) growths; brown algae; diatom growth; slimes; colored patches on rock or substrate; etc.?
Water changes (how much and how often). Kind of artificial salt youââ"šÂ¬Ã¢"žÂ¢re using. Kind of source water you are using? Have you analyzed your source water for the above chemistries? When did you do these tests last? What is the TDS of your source water?
List what you added or taken out of your aquarium system (living, decorations, and equipment) during the past 6 weeks.


New member
Thanks for the response. As to your questions:

1. The tank is about one year old, it cycled in march, 2005.
2. 300 gallon, 96x24x30
3. Filtered by live rock and Deltec AP702 skimmer

4. Tankmates are: powder blue tang (6"), kole tang (4"), sailfin tang (7"), harlequin tusk (7"), pair of crosshatch triggers (8"), queen angel (7"), bicolor angel (5"), auriga butterfly (4"), lawnmower blenny, a couple damsels, toby puffer, and probably a couple i forgot.

5. Sump/fuge with macro

6. QT for 4 weeks, no disease ever (on any fish) apparent

7. I feed all my fish daily and it is not targeted at any fish. I let them eat what they want. Food consists of chopped seafood, nori, Ocean Nutrition variety pack cubes, new life specturm pellets and ON formula 2 flakes.

8. Selcon is the only additive.

9. pH is 8.2 and fluctuates probably from 8.1-8.3. SG is currently 1.025. Ususally never gets below 1.022. Ammonia and nitrite are unreadable, nitrate is 20. Don't test for the rest. Temp is controlled at 78-80.

10. No algae or other problems aside from a fine brown algae that I clean about once a week from the front of the tank.

11. Water changes are done every other week, 30 gallons. All water is bought from LFS (NSW from San Diego). I have not analyzed the water from the LFS in months.

12. The only thing removed from the tank in the last six weeks is some LR rubble (about 2 cups worth).

Thanks for all your help.



New member
From items 4 and 10 I'd say the bio-load is high. I would not expect a one-year old tank to be dealing with 'brown algae.' The system should have settled in by now.

Perhaps have you added too much fish, too quickly? The biological activity can be suitable to handle ammonia and nitrites, but there are many more organisms (micro and otherwise) coming and going in the first several months until they stabilize (more or less) and the tank chemical and biological activity gets into a pattern. If the bio-load changes appreciably and often (like adding large fish too quickly) the tank doesn't get a chance to settle into a mature pattern. When a tank reaches its state of maturity, brown algae usually goes away. Its presence indicates the tank is still developing along these lines (i.e., still maturing).

With that much in the way of bio-load I'd watch out for carbon dioxide problems/low oxygen problems, which can develop even with a good macro refugium going. This concern can develop simply by not bringing in enough fresh air from outside, and pushing out 'used air' from the places the equipment is running. An indicator of this concern can be fluctuating pH. If your system experiences that pH range you posted in 24 hours, I'd suspect the above to be a contributing factor.

I don't know the entire volume of your system, but a 30 gallon water change every other week is light. That is less than 10% every other week. I'd move that to 10% weekly of the actual volume of the system as a minimum, especially considering the bio-load you have going.

Back to the tang. . .The tang could be stressed from the company. You have a large tank (good) and that size tang would do well in it with one or two (only) of the other large fish you listed. The low-end water changes can be causing a creeping problem in water quality of constituents you/we can't/don't measure/test.

I would do an immediate 50% or more (if you can, up to 80%) water change and see if the tang perks up or changes. Note any change in your fish from this large change.

Water around San Diego would not normally be NSW. Do you know where exactly this water is collected? My only concern about using NSW straight (without letting it sit or running it through a UV) is the potential of introducing unwanted microbiologics into the aquarium. I hope you either let the water sit (or it has sat at your LFS for at least 4 weeks) or that you run the water through a UV/ozone system before using it. Either would be insurance for keeping your tank disease-free.

Keep us informed! Good luck! :rollface:
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New member
I will do the water change tomorrow. As for the NSW, I was told it was free from an aquarium or university in San Diego and my LFS stores it for cutomers. He charges only enough to cover the transport.


New member
Unfortunately, I awoke this morning to find the Naso dead. I still plan on doing the water change and analyzing the source water. Any idea as to why this could start so suddenly?


New member
The onset follows the way an infection of Marine Velvet (Amyloodinium ocellatum) would progress. I hope it isn't that. In case you're not aware of this disease:

Sometimes the onset of MV is so fast, all the aquarist knows is going on is that their fish is breathing fast. It's one of those "disease" end of the spectrum possibles I first mentioned in my first post. Tangs, as a matter of fact are usually one of the fish that succumb to this disease early on.

Watch your other fish very closely. You're looking for rapid breathing, any signs of flashing (scratching on surfaces), shaking their head (wagging), darting suddenly, and showing tiny white spots (that are hard to see even when you know what you're looking for). The above article will help you with what to look for.

When was the last fish or specimen you added to the system and did you quarantine it before putting it in the display?

You might start thinking about how you would treat your fish if this is a disease.

If you're lucky, the fish died of something that wasn't 'catching' or likely to spread.

Look very closely at all your fish at least twice a day. If you still have the dead fish, look closely at it and see if you can see any spots on it, signs of infestation, flukes, worms, etc. I don't know your profession, so I don't know if you are able to perform any kind of post mortem investigation, but if you can't do this and you are really motivated, take the dead fish to your nearest and largest public aquarium or college where they have people that can and are willing to perform such a post mortem.

Until something else develops that's about all I can say. Monitor the tank specimens closely. Do the large water changes for the next 2 or 3 days and see what reaction the fish have to the new water. Look for any difference (increased appetite, more active, more in the open (less hiding), etc., etc.) between the before and after water changes behavior or appearance.

I'm sorry for your loss. Considering the bio-load you have going, I would recommend not replacing this guy. :(