When are nitrates too high for......

[optix]

An oscar and Jack dempsey, I just did a water change and the nitrate levels are still 30 ppm, they were 60 ppm. I was just curious what is lethal to these guys. I am gonna change the water again tomorrow, so I can drop them even more.

[rus]

nitrate will not kill the fish unless at very very high levels. like more than 2500ppm(ball park figure). and nitrates are not harmful to freshwater fish at normal concentrations. but they are used as a good judge as to when to to water changes on non planted tanks. most people shoot for less that 20 ppm. if yours are at 60 then i suggest doing more water changes. what is your current schedule?

[predatorcichlid]

It also depends on the fish. Wild caught fish and certain other species are more sensitive to nitrate levels then captive bred fish are. Clown loaches, discus, some african cichlids will show ill effects before other fish will. Even though it takes a high level of nitrate to kill most freshwater fish there are other things to consider. Elevated levels of nitrate can slow or stunt a fishes growth and if exposed to in for extended periods of time can also affect there immune system and thyroid function (again growth). Most freshwater tanks do best when nitrate levels are kept below 100 PPM. Ideally the level should be 60 PPM or less. For rapid growth or fry tanks the level should be kept to less then 30 PPM. This is just rule of thumb figures, it really depends on alot of factors like oxygen levels, and maturity of your Nitrobacter SP bacteria in your tank. With out going into more detail under 100 PPM will be fine for your fish and less is usually better.

[optix]

Well predator, your pictures speak for themselves and the fish are gorgeous so I go with what you say. Im gonna do my best to keep it at 30 or less for good growth sake

[rus]

**** i guess my pictures suck!