hi everyone as you may have seen i lost 2 os a couple of weeks back one was a little deformed and had a growing problem the other died of battle wound to his mouth caused by ozzy my big o,now he is getting weaker ,he is not eating nothing even his fav earth worms ,and now he is lying on his side just like the other 2 went ,i have checked the water very slight amonia ,nitrate was 80 so did a 50% water change to bring it down to 40,ph 7.2 pleko and catfish are fine ,do you think he is missing his mates even though he killed one of them water temp is fine i cant think of anything else ,do you think there could be a virus in the water that just effects os,open to suggestions,

Sorry to hear that your fish isn't doing too well. The fact that your nitrate level is so high indicates such reasons as overstocking, overfeeding, or not enough water changes. You state that you did a 50% water change and lowered the nitrate down to 40 ppm. This is still the highest we would recommend. 80ppm is very high and fish will start feeling the effects of this, I don't think it would kill them though, but it could stress them which in turn could make them susceptible to illness.

Also, you have ammonia present, this is also not a good sign that things are running smoothly in your tank. Please remind us how big your tank is?

Where some fish do pair for life, I'm not so sure about the Oscars, I know angelfish do. However, it's difficult to say that if we lose their mate, do they act in the same sort of way that a swan does? I sort of felt it, I think they would just get over them and find another mate, I don't think it would affect them. I've had cases where Oscars have been friends for years and even laid eggs together, one of them has then died, I've never seen any signs of depression, so to speak.

If you're not able to keep your nitrate levels down, and you still have ammonia present, I would seriously think about rehoming some of the other fish. If your water is in poor condition, it's going to be very difficult to improve that if you have too many fish. Also, please reduce her to sleep feeding from now, maybe once every two or three days

the tank is 350ltrs ,there is 1x 9inc plecko ,1x 3inc cat fish and 1 x 5inc o, the water test kit we have suggests 40ppm or below is ok for freshwater aquariums,and the amonia test card shows yellow as being a good colour with zero amonia and then going into darker greens when there is and my test was nearly yellow perhaps 0.25 amonia ,but i will keep checking it,

Is it a Jewel aquarium by any chance? The first aquarium I ever had was a Jewel Trigon 350. This works out to around 77 UK gallons. That's big enough for an adult Oscar and a couple of smaller tankmates. As it stands, I don't think you are particularly overstocked since the fish are relatively small.

What filter have you got? 40 ppm is okay, but we don't like it to get much higher, have you checked your tap water for nitrate?

Okay, I'm going to suggest that you don't feed your fish for the next few days. Don't worry, they will be perfectly okay. We just need to try and get this small ammonia problem sorted out, if you keep on feeding, it's going to be a little more difficult to do this. Have you cleaned your filters in the last few days?

the tank measurments are 150 cm x 65cm x 45cm its not a jewel, i run 2 fluval 305 filters and have not cleaned them out since starting the tank up 5 months ago as when i do weekly water changes the volume of water passing through has not droped in any way there is plenty of presure,and on every water change i put stress coat and nutrafin cycle to boost up the bio in the filters ,

I think you should consider making sure that the filters haven't built up too much crap inside. Your filtration is good so that's no problem. Like I said before, either stop, or reduce feeding dramatically for the next few days. At least this will reduce the amount of waste going into the water. When you do a water change, don't test the water straight after, test the water a few hours later, or the next morning.

remember, if you clean your filters, clean them in existing tank water, not tap water

thank you , i will stop feeding them for a few days and do a water test tommorow,and let you know how ozzy gets on,

Good Luck Tj!!!! My fingers are crossed for you and Ozzy!

I have nt feed ozzy today, i have just done a water check, after i did the 50 % water change yesterday!! ammonia still 0.25 nitrate 40 nitrite 0 . should i do another 50 % water change again today ? i also tested my tap water for nitrate it was 10 ??

No, you don't need to carry out another water change, .25 is not overly bad, not good, but not life-threatening. Test water again tomorrow and let us know what the ammonia reading is. If your nitrate in tap water is 10, obviously you're always going to have slightly higher nitrate at the end of a week. However, nitrate isn't too much of a cause for concern as it is not anywhere near as toxic as ammonia or nitrite

is there nothing else i can try for ozzy,he is on the bottom of the tank lying on his side and it is so frustrating to watch ,his breathing is very shallow he looks like he is giving up. if he goes i will not get another oscar they dont seem to stay alive ,

Am I correct in saying that you don't have any more fish, this is the only one left in the tank? I don't suppose you are not going to lose anything by carrying out another large water change, however, if your ammonia is indeed .25, I really don't think that is high enough to cause a huge problem, I suspect that the fish has already been affected by poor water quality. I know that's you out in the up the road from me so I don't see any point in me suggesting you going out and getting some " Prime" which may believe the fish from the toxic ammonia. If the fish is still with us in the morning, you could try this as a last resort.

The only problem with carrying out another large water change is you may cause more stress to the fish, but like I said, I don't think you're going to lose anything by trying this.