I have 1 oscar about 25 cm in length that is always happy and Just this morning, I saw him sitting at the bottom of the tank. Last night before I went to bed, I still saw him swimming happily and eat.
Other symptoms:
1. I also notice a thin whitish film on the right eye.
2. Occasional tail twitching
3. On the lower fins, i can see something like entrailing line of slime coming from the edges of the fins.
4. no rapid gill movement
5. the side swim fins (left and right fin...dorsal fin?) still moving.
6. Sitting on the bottom of the tank with the head/front part slightly more downward than the rear/tail part of the body.

Few days ago, I removed the gravel (all) because I wanted to change the gravel to the bigger polished pebble stone. I thought it would look nicer.

Here is my tank setup: 4ftx50cmx40cm (water height)or arond 240 ltr of tank (60 US gallon?)

I have done water test and the dont look good...
Water test as tested with nutrafin

1. Ammonia 1.0
2. PH 6.6
3. Nitrite 0.1

(cant test other stuff as I dont have the tester, my nutrafin can only test ph, nitrite and ammonia)

Here's what I have done so far before I found this website:

1. 40 ltr water change
2. Added pure salt or rock salt half dose (30 teaspoons)
3. Half dose of tri-sulfa (because I suspect bacteria invading on the eyes plus in the past few days, it was very hot here in where I live. Temp went up 44 degree celcius) Tank water went up to about 30 degree celcius or more than 82F)

I have attached some pics. Not really clear but you can see some slime entrailing from his lower fins. Can't get clear pic of the eye though.





I will continue changing water from now. Should I add salt everytime I change the water? What is happening with my friend here?

EDIT: just few more info I forgot to ask. I am using 2 filters on this tank. One is fluval 305 you can see the outlets on the left side of the tank from the pic and one is a helper internal cannister filter (forgot the capacity but its about 35 cm in height from the tip of the filter to the bottom)

At the moment because I am applying tri sulfa as for precaution for bacterial invasion, the fluval is being turned off (because of carbon media in the filter)and cleaned. So I am only using the helper filter only because of tri sulfa application. (no carbon in the helper filter, the media is purely ceramic noodle)

I use 2 filters regularly in this tank to help pick up the debris on the other end of the fluval outlet. What is your opinion about this?


Many thanks

the mere fact that you have ammonia and nitrite, the oscar is in distress.
plus the sudden change of environment when you change the substrate.
doing large water change can ensure lowering those toxin but without
testing kit...no way to know. ammonia and nitrite should be o.
shutting off the other pump could compromise the conversion of toxin
to nitrate....if i were you, i will just remove the carbon and let
the system run....

i am sure you did cleanse the rocks before putting them inside.

1st I wouldn't turn off the filter. your bacteria inside will die and it will need to be recycled if it has been off for any length of time. re cycling will take up to 6 wks. As said remove carbon and run it. how long was it off for?

2nd by the sound of your description it could be slime or velvet. i am not totally sure but your treatment may cover this. that said having high ammonia could leave the eye with a film and make the fish produce more slime. so you could just have water issues that could be fixed without treatment. you need to carry out regular water changes of 20-30% tank volume and test your water to make sure its within a safe level. I would aim to keep both ammonia/nitrites below 0.25. and remove it altogether once you have your filters back under control.if the filter has been off a hour or so it may work and not need to be recycled.

Do you know what rock material that large white rock is made of??? it don't look familiar to me so has me wondering???

Thank you so much for the quick reply.
I just did what you guys suggested, i.e. keep the fluval filter running and took away the carbon.

At the moment, the oscar is swimming better than before but still appears weak. Thank God he also ate a little bit but I didnt allow him to eat much. I was just testing if the appetite has come back. The film on his right eye has disappeared. I am just surprised this happens in only few hours. It may have not been bacterial infection... But in 10 minutes after (in fact, while I am writing this...he is sitting again at the bottom right and move little bit around, not as energic as he used to be...

Ok now questions:

1. Since I have applied tri sulfa, what should I do now?
2. Last water test reading is ammonia 1.0, nitrite 0.1 PH 6.6. Water temp 28 degree celcius. No change. (I have done water change this morning, should I do again in tonight?)
3. Should I put the carbon back in to neutralize the sulfa?
4. I didnt think of the bacteria could die in the fluval filter as I turned it off, what should I do now? Last time I checked when I took the carbon out, the media are still damp and the bottom tray is still wet.
5. I have unused bioballs (about 50 pieces) would it helpful if I put them around the substrate? I cant put them in the fluval media tray. Got no room. I was thinking of putting them in a filter stocking and hang it on the back side near the black internal cannister filter (aquaworld) but it will not look good =D

About the stones, yes I have given them a dip wash in tap water before I put them in the tank. I did not realize the substrate change will give this much impact as I thought my gravel was full of organic debris. Thought by changing the substrate to bigger stones, it will be easier for me to notice oscar's poop as his poop is big.

marcus wrote:


It is river pebbles. Polished. It has smooth surface because it is polished.

Its good you got the filter running again. the cycle may still be damaged cos water needs to to be flowing through it, so the bacteria has oxygen, but you can't do anything about that now other than run it.

we need to get the ammonia/nitrites as low as possible. at least to 0.25 anyway so change water until it reaches that reading.and then carry on water testing/changes daily if needed to keep the reads at 0.25 or lower. the water changes will remove any meds that are in the tank so NO don't put carbon back. in fact you will not need to use carbon again if you have oscars. not many member use it.

Lastly we need to keep an eye on the slime. I am not certain weather its the poor water or parasites. if it is the poor water by doing the above it will clear up. if you have good water and the slime gets worst it will need to be treated. so you have a choice. I can't make it for you I think thats unfair.

1 treat the tank while you continue changing the water. to do this add enough medication to cover the water you remove. ie if you remove 10g you add meds to treat another 10g

2 don't treat the new water and see what happens.

what ever you choose your main aim is to get the water, ammonia/nitrites as low as possible or at least to 0.25. if you change 20% tank water and next day ammonia/nitrites are high change more water. feeding less or every other day is better while you you try to control the ammonia.

PS. i forgot if you have any white vinegar pls test the rock. take out rock and put a small amount of white vinegar on it. look to see if it fizz or bubbles. then wash before you put back.

marcus wrote:

I will. Do i have to dry the rock first or put vinegar straigt away when its wet?

Also using "prime" water conditioner will help, has it reduces ammonia/nitrites. you can add "prime" to your tank and then continue to use it on all new water that you change. its better than some other conditioners as it helps remove ammonia/nitrites and also fast cycle the filter too.

Ummm ok...now he is attacking the rock! He opened his mouth opened and attacked one or 2 rock pebbles and then he tried to attack the black cannister filter???!!! What is going on with him omg.... is he going nuts? I heard the high ammonia can damage fish brain...is he getting crazy or something...oh i dont like this.

What is "prime" water conditioner? Dont think I've heard about it here in Australia...I use seachem water conditioner. Was about to get API ammonia lock but the guy told me its best to try water change first...i must agree...i am sure you are agree with this too?

I will change the water again after this asap...

As we speak...he is attacking the rock again...

md1017 wrote:


wipe it with a cloth. it don't need to be fully dry cos drying out a rock can take days even though it looks dry. wipe it and test. wash and put back. if it bubbles or fizz don't put back.