Please help.

Vivekcichlids

Black Skirt Tetra
MFK Member
Mar 9, 2020
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I have a 5feet long 90 gallon tank. I've had an Oscar in it for almost 2 years. He was really healthy and grew big from a very small size. But recently I lost him all of a sudden. He was gasping and died. I do the water changes weekly 40-50% always and it has worked for me really well. I brought another Oscar after him and he died too. Then another he too died. And it seems my pleco and a small convict cichlid are completely fine and healthy but my Oscars can't live. I changed water. 50% in the morning and then again 50% in the evening just assuming it could be ammonia problem ( as I don't have access to a test kit here) but nothing worked.
I have a 2.5 feet long sump as filter, a bubbler and one internal filter too.

I am so stressed and disappointed. I've been keeping fishes for almost 20 years now. Never had this issue. I feel like I can never keep Oscar again. I'm so frustrated. Please help.
 

Rocksor

Blue Tier VIP
MFK Member
Nov 28, 2011
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Test your ammonia, PH, and nitrites in the tank and your tap water. Test tap water ph after 24 hours in a cup. You need a liquid test kit

another possibility is the convict stressing out the oscars to death while you are not looking

how big is the convict
 
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Vivekcichlids

Black Skirt Tetra
MFK Member
Mar 9, 2020
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No. Convict is small and my first Oscar which died was 10 inches. I don't have an access to a test kit here. My other tank has Severums in it. Very healthy. But this tank seems to have a problem. Do you think my cycle is broken?
 

Rtc/tsn

Giant Snakehead
MFK Member
Apr 22, 2021
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No. Convict is small and my first Oscar which died was 10 inches. I don't have an access to a test kit here. My other tank has Severums in it. Very healthy. But this tank seems to have a problem. Do you think my cycle is broken?
On the fish that died was there any teared fins, red fins, or anything that shouldn’t be on the fish?
 
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SourAngelfish

Candiru
MFK Member
Jan 22, 2021
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How come you cannot test water? I feel its very important to have params in order to assess this situation
 
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