What do I do when my nitrate levels are too high?

Question

I have had my 50 gal tank for two years. I have never had a problem with nitrate levels until about 6 weeks ago. I noticed my fish started acting depressed and would only come out when I was feeding them. I went to Pet Smart and one of the employees told me to add 7 tsp's to the water. Well the next day my goldfish would not move and it's scales were sticking out. The fish looked extremely bloated. I took the fish to Pet Smart and they said he had Dropsy. They said that was the worse case of Dropsy they had ever seen. They put him to sleep for me. Well now, I am again having the same problem as I started out with, my Nitrate levels are too high. I need to know a safe way to correct this problem without killing anymore of my fish. Please Help.

Answer 1

The significance of nitrates in the aquarium is arguably less understood by fish keepers than the effect of ammonia and nitrites. Although nitrates are not directly lethal in the way ammonia or nitrites are, over time high levels of nitrate have a negative effect on fish, plants and the aquarium environment in general.

Effects on Fish

Fish will feel the impact of nitrates by the time the levels reach 100 ppm, particularly if levels remain there. The resulting stress leaves the fish more susceptible to disease and inhibits their ability to reproduce. High nitrate levels are especially harmful to fry and young fish, and will affect their growth. Furthermore, conditions that cause elevated nitrates often cause decreased oxygen levels, which further stress the fish.

Other Effects

Elevated nitrates are a significant contributor to undesirable algae growth. Nitrate levels as low as 10 ppm will promote algae growth. Algae blooms in newly setup tanks are usually due to elevated nitrate levels. Although plants utilize nitrates, if nitrates rise faster than the plants can use them, the plants can become overgrown with algae, ultimately leading to their demise.

Where Do Nitrites Come From?

Nitrates are a by-product of nitrite conjugation during the latter stages of the nitrogen cycle, and will be present in some degree in all aquariums. Detritus, decaying plant material, dirty filters, over-feeding, and over-stocking the tank, all contribute to increased production of nitrates.

Water used to fill the aquarium often has nitrates in it. In the United States, drinking water may have nitrates as high as 40 ppm. Before adding water to your tank test, it for nitrates so you know if the levels are unusually high in your water source. If nitrates are above 10 ppm, you should consider other water sources that are free of nitrates.

Desired Level

In nature nitrates remain very low, generally well below 5 ppm. In freshwater aquariums nitrates should be kept below 50 pm at all times, preferably below 25 ppm. If you are breeding fish, or are battling algae growth, keep nitrates below 10 ppm.

How to Reduce Nitrates

Unlike ammonia and nitrites, the bacteria that remove nitrates do not like oxygen rich environments. Therefore, conventional filters do not harbor the bacteria that remove nitrates. Although special filters exist that will remove nitrates, such devices are usually expensive compared to other filtration units.

Keep the tank clean – Waste ultimately produces nitrates. Cleaner tanks produce fewer nitrates in the first place.

Don’t overfeed the fish – Overfeeding is a significant contributor to excess nitrates and other undesirable wastes, such as phosphates.

Water changes – Performing regular water changes with water that has little or no nitrates will lower the overall nitrate level in the tank. RO/DI water is an excellent choice for keeping nitrate levels low.

Keep live plants – Live plants utilize nitrates, and will help keep nitrates in check.

Use nitrogen removing filter media – Instead of an expensive denitrator or special filter, use special media in the filter you have. Although they will not lower nitrates dramatically, if used together with other methods the net result will be beneficial.

Answer 2

Sounds like you have the dropsy caused by poor water parameters. What did petsmart tell you to add to the water? Since it is petsmart I'll guess it is aquarium salt they told you to add. Sorry but salt will not affect the nitrate levels whatsoever. Fortunatly nitrates are an easy problem to fix. All you have to do is change some water. Start out with smaller water changes every other day of about 10-15% until you get the levels in check, then change between 15-25% each week to keep them in control.

The most likely causes of high nitrates are:
1. too many fish
2. overfeeding
3. too much organic waste
4. not enough water changes

For #1, please post what fish you have and how many of each and people can tell you if you are overstocked
For #2 simply reduce feeding
for #3 and 4 just change water

Regular partial water changes once a week will keep nitrate levels down in any aquarium that is properly stocked and not overfed.

Answer 3

Water change, water change, water change! The only way to keep nitrates at safe levels in your tank is to do at least 20% water changes in your tanks weekly and a good gravel vacuuming once a month really helps too. More often if you're overstocked.

Also, consider investing in a nitrate testing kit and checking the levels a few times a week to get a feel for how fast they're rising. You don't want to see them go over 25 mg/l -- some hardy fish can handle 40 mg/l. If you have to change water more often than once a week to keep the levels safe, then you're definitely overstocked.

Answer 4

I have to agree, 7 tbs of what? How many fish do you have in the tank and what exactly are the water quality readings? Ammonia, Nitrates PH?

It does sound like dropsy, which is caused by poor water conditions.

Do you have plants in your tank?

Unfortunately the only way to drop the nitrate levels is to do water changes. you should be testing at home daily to keep the problem in check.

As your goldfish grow, they are going to produce more waste, as well as the extra food you are feeding them. A weekly maintenance schedule is your best defense.

Answer 5

Two thumbs up to *Future Veterinarian* if I could. Nothing more to say on the subject, she covered all the bases.

MM