So I noticed that my oscars fins have started to rot and I don't know what is going on. I took my water in to get it tested and all the chemical levels were fine, except the nitrate levels were really high (almost off the color chart). What can I do to fix this problem? Can this cause the fin rot or should I medicate the tank? I already put a low dosage of salt in the tank but after two days his fins haven't gotten any better and it looks like skin has come off his side (almost like a scratch)

ok i would first start with a large water change (ie: 50% or more if you can!!) this should help your levels... what is the size of your tank and filtration? the next thing i would do is go out and get a liquid test kit so you can monitor your own tank levels the api master kit is probably the best bet and readily available... hope this helps ya out and good luck!!

The only way to reduce nitrates is to do water changes. Buy a test kit and test your water. If the nitrates are above 40 do a 50% water change. Repeat this every day until your nitrates are below 40. Once this is achieve move to weekly water changes

You need to be doing a water change every week. Test for nitrates before the change. If your nitrates are above 40 then you need to do bigger or more frequent water changes. Most of us on here do 50% every week.

Make sure you dont over feed. If your fish are 3 inches or bigger only feed once a day what they will eat in 2 mins. Dont feed anymore than this no matter how hungry they look, oscars are professional beggars. If your fish are less than 3 inches feed twice a day for 2 mins each time

The information we need to know are how big is your tank, what fish you have in the tank, what temperature the tank is, what filtration you have and how long has the tank been runnning for

Huntert311 wrote:

large regular water change can correct this problem


salt will not be effective if the water is not in good condition....in the first
place, salt is not needed if you have pristine water.

yes, fin rot is a by-product of bad water condition. water being fine is useless.
there should be data as in ammonia=? nitrite=? nitrate=? and pH=? so that we can give
proper evaluation