yellow tang sick

Question
QUESTION: i have a yellow tang and a snowflake eel and a purple algae eating fish in a 46 gallon tank the specific gravity is 1.022, ammonia is at 0.0, nitrite is at .2, ph is at 7.8, last night when i went to bed the tang looked fine now this morning when i woke up i checked in on them and the tang is swimming sideways and he looks extremely skinny and the purple fish was dead what would you guess is wrong with my tang this is a mature tank

ANSWER: Hi Heather. You should really be concerned with your nitrite if it is at any level in a mature tank. Typically a well maintained cycled tank should not get any reading for nitrite. This can be toxic to fish even in small amounts. Have you tested your nitrate to see where your tank stands on that? I would guess that if you are getting a reading for nitrite then you are most likely getting an even higher reading for nitrate. Some where in your tank your biological filtration is not properly functioning. You should do a partial water change to help bring down the nitrite and test for nitrate. Are you using tap water for your top offs and partial water changes or do you use reverse osmosis or distilled? I never recommend using tap water unless it is filtered and treated. There are lots of nasty chemicals that can come in with a main water supply all of which can be very toxic even in small quantities to your saltwater fish. Are there any signs of illness such as white spots, a powdery appearance, open sores or wounds, cottony looking tufts or damaged fins? Are you providing your tang with lots of green algae to eat? How often do you do your partial water changes and any other regular maintenance? Your ph is a little on the low side and if maintained at this level can have a detrimental effect on your fish over time. When in doubt about the health of your fish I always recommend doing a good cleaning and partial water change using only reverse osmosis or distilled water. Freshen up any carbon you may have in your tank and check all your levels thoroughly. Make sure you are feeding a good variety of frozen meaty marine fish food along with the proper vegetable matter for your herbivore fish and possibly incorporating the use of a good fish food supplement such as Selcon. It is practically impossible for me to tell you exactly what could be wrong with your tang. With no outward signs of illness and very little for me to go on as far as the info provided to me all I can do is tell you what may be wrong with your tank. I would be very happy to assist you further but in order to do so I will need a little more info. How long have you had your tang? How often do you feed? Has he always looked thin or did he suddenly become thinner and started acting differently? Get back to me with your Temp., nitrate, and feeding schedule along with the other questions I have asked you and I could help you a little better.

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QUESTION: the nitrate and nitrite both measure at the lowest possible reading on my test kit, i use tap water and i use amquel plus to detoxify it, the tang's top fin looks very bad its like the flesh is coming off the bone this is a new problem since the first question, he wasn't skinny before it just happened, i have been using mela fix,i do water changes every 2 weeks, i used pH buffer last night to fix the pH, new carbon, had tang for a month, i feed once a day, temp is 78,

Answer
From your description and the newest symptom, it sounds like either a case of something toxic entering your water or a bacterial infection or both. Even though you use a tap water additive to detoxify the chlorine and chloramine in the water supply, there are are a lot of other toxins that can enter your tank through your tap water that this conditioner will not be able to neutralize. Some of the substances used to treat your tap water will actually have an even more toxic effect when mixed with saltwater. I can never in good faith recommend using tap water with any additive over reverse osmosis or distilled water for top offs and partial water changes. At this point with the fin being sore I would have to say that your tang has now got a bacterial infection. Treatment with an antibiotic food should help but there is something wrong with your water, nutrition of the fish or a genetic predisposition that has caused this problem in the first place. A healthy well nourished fish will have a good enough immune system that when a bacteria invades, it is able to use its own defenses in order to fight off any infection from getting as far as it has in your tang. Your tang has a lowered immune system making it more susceptible to these infections and unless the reason for the lower immune system is fixed there will be no hope for a cure. Some of the things that causes the immune system to be lowered is poor water quality, toxins entering the tank either from outside sources or manufactured within the tank, bullying, improper nutrition and over medicating or too many additives mixed together. Try doing a partial water change using distilled water instead of your tap water to see if there is any improvement. Often even the worst cases of infection can be cured with out medication if the conditions in the water are improved. You have already lost one fish and have nothing to lose except for a little money, in doing another large partial using high quality water with no additive like distilled or reverse osmosis. Bacterial infections do not happen to a fish that is healthy prior to the infection and there is always the possibility of a genetic problem causing the lowered immune system.