Bloated Nasa Tang

[bluespotjawfish]

I've had this Nasa Tang for about a week now. Looked fine when I got him, and he had been at the fish store for about 3 weeks. He has been slower than I expected to start eating, but is now eating light-normal. He also seems to be a bit more shy and darkens in color often. Yesterday, I noticed he was a bit thick in the belly, but today it is huge. I swear he is going to pop. What is wrong with him. There are no marks on his body, or other signs of illness. No other tank mates look like that (though one of my Bluespots from the same store isn't eating much yet).

Sorry can't get any better pics than these.

[Woodstock]

Yikes! If it isn't from eating, then it may be a bacterial infection or possible constipation? What are the water parameter? salinity? temp? Nitrates? Ammonia? NitrItes?

[bluespotjawfish]

Salinity 1.012 (I have been slowly lowering this over the course of the week)
Ammonia, Nitrite 0
Nitrate 10
Temp 78

Just tested my pH it was low 7.6ish, could that have caused this? I now have it raised to 7.8. I also did a 30-40% water change tonight.

Not from eating, I am feeding lightly. I have had fat, dumb, and happy nasa before, this is different.

[Woodstock]

Yes, the low ph and low salinity could be wreaking havoc on his internal organs. If he doesn't get better, you may want to forgoe the hypo treatment.
Make sure you're testing the salinity with a refractometer. I suggest calibrating it with ro/di water for hyposalinity situations (and using the pinpoint salinity fluid to calibrate for 'normal' salinity). PM Boomer to get his opinion. The salinity is critical during hypo treatment so do all you can to make sure it is accurate.
Good luck and keep us posted!

[DrHank]

I'd recommend that you end this hypo treatment and get him back to normal salinity and ph fairly quickly. I'd be doing 50% water changes (probably twice daily) until both salinity and ph are back to normal.

At the risk of sounding stupid, may I ask why you were performing this hypo salinity procedure? Some marine fish do acclimate to brackish or even fresh water however, the Naso tang spends most of it's life on the outer edges of the reef. It isn't one that will.

[NaH2O]

DrHank - hyposalinity is a very effective treatment for ich, and can also be used in QT when introducing new livestock. Fish under stress can have osmoregularity issues. Hyposalinity can decrease stress by allowing the fish to save energy normally used in osmoregulation. Provided pH is maintained along with other parameters such as temperature, ammonia, nitrites, and nitrates in a QT, I think it is a great procedure.

Here is some more information on osmoregulation:

Osmoregulation: Please give me a drink!

Marine fish (teleosts) have the exact opposite problem to that encountered by freshwater teleosts. Their body fluids are, again, 1/3 of that of sea water but this time they are in sea water so their body fluids are hypoosmotic to their environment. As a result they will tend to lose water by osmosis to the environment through their skin but mostly through their gills. Consequently, they have developed mechanisms and behaviour to compensate for this water loss. Firstly, the kidneys of marine teleosts are modified in such a way that very little water is extracted from the blood, some species even lack certain kidney structures and can't eliminate water (Gordon, 1977; Moyle and Cech, 1982). This results in a reduction in the loss of water by the production of urine. However, water is still being lost by the gills and this cannot be stopped, so the only method left is to somehow replace the water as quickly as it is lost. Marine teleosts accomplish this by actually drinking water, the most reliable drinking rates reported in the literature range from 3-10 ml/(kg hr) (Gordon, 1977). However, drinking water by itself cannot solve the problem, a complex series of events must first occur in the digestive tract. These events are not yet well understood but it is known that most of the water is absorbed as are the monovalent ions Na+ and Cl- (they are, after all, drinking salt water!), while the divalent ions (such as magnesium and sulfates) are excreted by the kidneys (Gordon, 1977). Sodium (Na+) and chloride (Cl-) also move by diffusion into the body through the gills. Therefore, Na+ and Cl- ions will accumulate in the body of the fish and must be eliminated, this is accomplished by special cells in the gills called chloride cells, which me these ions out of the body by active transport (Moyle and Cech, 1982; Gordon, 1977).

From the above information some practical tips for the hobbyist can be gained. Since marine fish must constantly expel various solutes, such as sodium and chloride ions, against an osmotic gradient, a great deal of energy is required. Therefore, anything that you can do to lower the osmotic gradient will benefit the fish in terms of energy expenditure. The simplest way of doing this is to lower the salinity of the water as much as possible, particularly for a fish in distress (i.e. diseased). This alone can sometimes be enough to ease their burden. Of course any such change must be extremely gradual and must not get to the point where the fish is in obvious stress. Another problem comes when invertebrates are added, especially the soft-bodied ones such as anemones and corals; a drop in salinity can be disastrous for them. Since marine fish produce very concentrated urine, their waste products can pollute a tank far quicker than a freshwater fish which produces much more dilute wastes. That is why you can usually put in many more freshwater fish than marine fish in the same volume of water. That is why paying attention to the water quality of a marine tank is so much more critical than in a freshwater tank. With the advent of dry/wet filter systems from Europe, the load in marine aquaria can now be greatly increased due to the superior ability of the filter to handle waste products. That is why the so called "mini-reef" systems are becoming so popular with hobbyists, many more animals can be kept in a smaller volume of water with little risk of pollution.

From: Quarantine Tank Methodology - Part 2

Lowering the salinity to less than that of natural seawater is a common practice among public aquariums, hatcheries and fisheries. Lessening the gradient between the internal fluids of the fish and their surrounding environment reduces osmotic pressure. This conserves metabolic energy that would normally be required for osmoregulation. Since hydromineral imbalances are inherent to stress in fish, lowering the salinity can reduce the effects of these stressors. Dr. Cheung (Cheung et al., 1979) reported that boney marine fish could be kept in a salinity of 16ppt “indefinitely.” I do not suggest maintaining marine fish in a salinity less than natural seawater on a permanent basis.

From: Reducing Losses Associated with Transport and Handling in Marine Aquarium Fish

Significant portions of post shipment losses are due to osmoregulatory dysfunction and stress-mediated diseases occurring within the first week after transport (Johnson & Metcalf, 1982. Carmicheal et. al, 1984). Stress in fish causes osmoregulatory dysfunction (Harrell & Moline, 1992. Weirich et. al, 1992). This can lead to mortalities (Tomasso et. al, 1980). Reducing the gradient (difference in salinity) between the internal fluids of fish and the surrounding ambient water alleviates water and ion disturbance ((Wedemeyer, 1996). Manipulating the salinity of the transport water upward for freshwater fish and conversely downward for saltwater fish is effective for controlling osmoregulatory disturbances and reducing losses (Carneiro &Urbinati, 2001). Fish held in water that is close to isotonic (the salinity of the surrounding ambient water is close to the internal fluids of the fish) have increased stress resistance (Lim et. al, 2000). These fish also display a significantly lower mortality rate at 7 days post shipment.

From: Quarantine of Marine Fish (Teleost) Using Hyposalinity

The other advantage that is of great interest with hyposalinity, is the reduction of osmotic stress on fish with abrasions or lesions. In theory, the reduction of the osmolar gradient between the internal tissues and the surrounding environment would be beneficial to injured mucus and epidermal tissue. This reduction in the osmolar gradient, in theory, greatly reduces the loss of water from the fish to the surrounding environment. The ability to maintain hydration in an injured marine fish too small to administer fluids could prove very beneficial. Many more studies, which are ongoing at this time, and sample collections remain to prove this theorized aspect of low salinity.

bluespotjawfish - Have you seen any feces output at all from your tang? There was a thread on another forum about a Naso with a similar problem (I'm not sure if I can link to the thread here?). I'll give a quote when I asked about the large lumpiness in the gut area of the tang:

"How can you differentiate between the lumpiness being a problem/infection, and one of food in the gut."

In new fish or fish you have never kept it can be difficult but in general it's more a matter of being familiar with the fishs' common appearance. With food, there will be small nodular bulges/lumps as the gut fills up, infections will be more rounded and usually pronounces in one or more area's as apposed to uniform "lumpiness" from eating. It's also knowing how much food is fed vs the size of the inflamation. If the belly area keeps getting larger and the food intake doesn't support it, there is a strong possibility of that or intestinal blockage.

BTW - the tang from the above quote was treated with KanaPlex in hyposaline conditions and made a recovery.

As for your pH issues, you will want to get that back up. Boomer has recommended in hyposalinity to use a product called: SeaChem Labs Marine Buffer (8.3). He recommends adding 1/2 according to the instructions and then check pH. According to Boomer, the pH will stay at 8.3, once you get it there using this buffer. BUT, don't think of this as a normal buffer. In a hyposaline QT tank it's Ok to use.

Lastly, when you do go to raise your salinity, do so in a slooow manner. Over the course of the week. Fish can withstand rapid drops in salinity, but cannot take rapid increases in salinity.

Hope this helps.

[bluespotjawfish]

Thanks everyone for your input.

Since I recently lost all my fish to ich, I am doing a QT with the hypo to PREVENT introduction in the display. I had already read most of what you posted regarding the hypo treatment, but I did make a major mistake in this process on this tank by not keeping a closer eye on the pH. It has stayed stable today at 78.5 (which is typical of my tanks). I have raised the hyposalinity a bit and haven't decided if I will abort it completely or not. Since I have to do it slowly either way, I have time to decide. No fish in this tank show signs of ich, but with all the work I have gone to I would hate to make a hasty decision (either way) that sets me back 6+ weeks and hundreds of $$$.

No changes in him today. He is still eating. Can't say that I have seen him poop, but the bulge is not bumpy at all. If I was to guess, the swelling does look more like retention of fluids for poorly functioning organs. Unfortunately, I am going out of town this evening and won't be back until Sunday. Wish him well in my absence!

[BoomerD]

NASA Tang? Isn't that the orange stuff the astronauts drink?

Sorory, couldn't resist...

There are many different possibilities, bacterial infection, problem with the usual tang "gut fauna", blocked passageway, or just in need of a good bicarbonate of soda to relieve gas..
I too would recommend you bring the tank back to normal salinity until the fish gets back to normal. It's very possible that for some reason, the hyposalinity has created a problem in the digestive system, and has things "plugged up"...or created some other problem...
Of course, it COULD be all those McAlgae burgers with french fried xenia you've been feeding the poor little fella...

[DrHank]

Nikki, thanks for the info. Goes to show you that you can teach an old dog new tricks if he wants to learn. I can certainly see that it would be tremendously effective for Ick. They would burst and drop off the fish (or vise versa).

I suppose that I've been fortunate thus far as I've never had a problem with Ick. I do however, run a UV sterilizer on a slow flow 24/7.

[Frankie]

Man! break out the tools! A roller pin is good for more then flattening the dough!
Just messin' with you Lorraine. I hope he gets better soon. Nikki and BoomerD seem to have given you great info.

[NaH2O]

BoomerD - I have to disagree with the recommendation to take the tang back to normal salinity. This fish is under less stress in hyposaline conditions, so whatever is going on here, the fish will be able to deal with it easier. I doubt the hyposaline conditions created this in any way. I suspect there is some kind of infection taking place that may have been developing previous to purchase. There are bacterial diseases that can cause abdominal distension. As an example: in the book, "Fish Medicine" by Stoskopf, page 636, under Vibrio Septicemia (which I'm not saying this is what it is, I'm just showing bacterial infection could be a cause in the case we are discussing....

Clinical Signs - The clinical picture seen in fish from which this organism is cultured is one of a generalized bacterial septicemia. Lethargy, skin darkening, scale loss, and occasionally ulcers can be seen. Fish become anorectic and may develop abdominal distension due to gas and fluid accumulation in the intestines. Respiratory rate may be increased, and gills are sometimes pale if anemia is present.

bluespotjawfish - The images of the naso tang in the thread I mentioned looked similar to yours. I only mentioned the lumpiness because a normal gut has uniform lumpiness. It is evident in your picture that this tang does not have that. As shown in in the last quote of my post, infections tend to have a more rounded pronounced look in one or more areas. I'm not taking away from the fact that this tang may have a large blockage of some kind. I would really watch to see if the tang poops at all. I'm not sure what kinds of meds you should start with, but I know the tang in the other thread I mentioned was put on Kanaplex, which treats bacterial and fungal infections.

This was the tang I am talking about (photo by donnales)



Hope this helps!

[BoomerD]

Nikki, I too doubt that the hyposalinity is the actual cause of the problem. My thought was that bringing the fish back to normal salinity may be less stressful than the hyposaline conditions.
Tangs are very dependent on the "gut fauna" to process their foods, which is why they are not recommended for copper treatment, which may kill those bugs that make it possible for the tang to be the great algae eaters they are.

[lcstorc]

Well since you mention copper, I believe this tank was previously treated with copper. Could that be the cause even if the copper tests to zero.
Lorraine am I wrong or is this fish in the tank you treated with copper or is it another tank?

[bluespotjawfish]

Duplicate post, sorry

[bluespotjawfish]

I'm back from the trip and everything is still kicking. Boy I hope I can answer all the questions.

Lynn - Yes, this is the tank that was treated with copper. My Palani Tang made it through the treatment. Copper was tested, reading is zero, I'm also running carbon.

Boomer - Maybe I need increase the veggies. He is the only veggy eater in the tank, so I have fed the veggies lightly. However, I had nori on a clip for a while and he didn't ever even touch it. The fried xenia is in the other tank.

NaH20 - My fish isn't bulgy at all, very smooth belly.

Frankie - You might be getting Hans Duo if you don't be nice to Mr. Nasa.

Dr Hank - Keep your fingers crossed that you never get it! I've always run a UV sterilizer on the display too.

I think the initial problem was caused by the drop in pH. I'm just not sure what problem that caused, or what I should do now. Still haven't seen him poop, but I haven't been home. I think I am going to have a drink and watch him for a while before I decide my next step (salinity up or down).

Edit - I just got a closer look at him and he appears to be substantially better.