Im worried about my young oscar, His fins have gone very dark almost black? He is an albino and only about 3in long, Is this normal? My profile pic is my oscar not the best pic but he wont keep still you can still make out the black edges, Thanks.

Welcome to the site


You are going to have to provide us with some information on your water quality before we can determine if anything is causing this colouration change on your Oscars fins.

Please give us some information on your tank setup. Aquarium size, filtration system, maintenance routine, i.e. water changes etc

There's not much we can do for you until we have some more information

Oh i didnt think of that...sorry,
Its 90 gallon tank with a fluval external filter, we did a water change about 9-10 weeks ago the nitrite water tests were good not done a ammonia test because i did'nt think there would be ammonia if the nitrate was ok? We have just lost our biggest fish a big tin foil barb?? but apart form loosing him we haven't lost any fish for years, The Oscar was ok untill about a week ago and he started to get black fins and one of our dollars has the same thing but he has always had it not sure if thats normal,

we have in our tank;
1 small Albino Oscar
3 large dollars
1 large silver shark
7 gouramis
2 plecks
and a couple of spiny eels we never see

Hello and welcome to OFL

First of all, you need to do 25-50% water changes WEEKLY. What were your nitrites and nitrates?

There is nothing wrong with your Oscar, mine is going through the same thing right now. As they grow they go through a kinda color morph.

Hi, Gosh i didn't realize you were supposed to do water changes weekly ooops, we have only got the nitrate test kit and it was a light sky blue colour and the chart said that's normal...i hope it is Im glad he is ok i thought it might be a disease of some sort, Thanks for replying.

OFL wrote:

agree with the boss. although oscar does change their color from time to time,
there are time that sudden changes was triggered by bad water condition.


this is why we need info. unless you have a huge tank, 9 -10 weeks without water change may be the reason why you lost some fishes before.

Its quite big but not that huge just over 90 gallons...I will do a water change tomorrow and a lot more often from now on....i had no idea i was supposed to do them weekly How often should i change the filter carbon and sponge etc? Thanks

there is a notion, though not scientifically proven, that carbon do cause problem
if not follow properly the correct usage. i am a technical guy that used to do
filtration works... and carbon is one major components. however, i am aware that
carbon itself has an effective useful life....beyond that, it will just mask the
water quality,thus, resulting to problem.

the sponge and other media are not supposed to be replaced regularly. they should
just be wash and cleaned with tank water.

We do not use carbon in the tanks even in the canister filters our fish act weard when we use it. and i think it was contributing to the problems with brutice(another thread) we just use the filters for the canisters we just cut them down to fit the otbs also adding about 5 lbs of crushed coral might help with the nitrates and nitrites. I have to use it in my puffers tank as for the coloration of t he fins theay are moust likley going threw a change. fish change colors spot and striped patterns all the time it is normal agree with the boss water changes need to be dont once per week at least 20%

I don't use carbon in any of my filters either. I think Paul is correct, it is not a foregone conclusion that you will have problems if you do leave the carbon in your filtration system, but it is thought that this could contribute to poor water conditions if the carbon is not changed on a regular basis.

My advice would be just do away with it and concentrate on plenty of bio media with some chemical media as well. Water changes on a regular basis making sure you always use a water conditioner to remove chemicals from your tap water. Only wash your filtration media out in tank water and look after it very carefully as it is the lifeline of your tank

Taiwan produce an albino looking Oscar with black edged fins. its not really an albino even though it has a red eye. I would still check on the water conditions to make sure. but has its so small I think maybe a natural change due to fish type/breed and growing.?

The black edge to your albino is quite common and its normal

however if you carry on as you are your fish will get sick and die. Check the site to find out how to improve your fish keeping skills but a few pointers are

Do a water change every week. Test your water before doing the change and if your nitrates are above 40 then you need to do bigger or more frequent waters change. I do 50% every week

Clean your filter every 4-6 weeks. Clean the stuff insude the filter in old tank water

Add dechlorinator before adding new water

Only feed what your fish will eat in 2 mins once a day and no more bo matter how hungry they look- oscars are professional beggars. Vary the diet