Old Tank Syndrome?? Fish Dying

nlmadison

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Sep 16, 2005
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What's the deal with O.T.S.? The guy at my LFS was telling me about this. I have an established 5 gal hex tank (w/Bio wheel) and suddenly my fish are dying. In the last 3 days I've lost 1 oto (new in tank - lived 3 days), 1 zebra danio (acually one of 5 my starter fish and has been in the tank for >1-1/2 years) and this morning my Beta (in tank 3 months) was dead. My water test are: Ammonia = 0, NitrAtes = 0, and Ph = 8.0 (I don't have a NitrIte test). I have well water and my Ph has always been at 8.0 so this is not a change. There's no obvious signs of illness in any of the fish. I don't know what else to look for. :huh:
 
never heard of it

guess i have to wait wid u on other ppl's response, m quite curious :confused:
 
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Can you please tell us what your normal cleaning/water change schedule was before this started happening? And how long exactly had the tank been set up? I personally am more likely to suspect one of your new fish having added some disease rather than old tank syndrome – the reason being your nitrAte reading. As a side note, are you sure it’s 0? Do you have a planted tank?

There are a number of general pollutants that lead to OTS which we can’t measure, but we can measure nitrates.
 
Admittedly, my tank changes aren't the best. But I'd say about 30% once a month and do a "breakdown" cleaning (i.e. take out fish & flush gravel, clean glass, deco, etc.) about every 3 months. I haven't cleaned the filter itself. I change the filter cartridge every couple of months but I rinse ~3 weeks or so. Tank was set up in Feb 2004. There are no plants. The only new fish was the oto which I bought with 1 other that's in my 29gal now and doing OK. Yeah, I'm sure of my NitrAte readings. I use the same test kits on my other tank and have had those test results duplicated at my LFS. The tank had 1 beta, 5 danios, 1 small snail & the 1 oto. These are my first fish losses since last year. Before the Beta I had a dwarf gourami in that tank with the danios and snail. I moved the dwarf gourami to another tank when I put in the beta.
 
OK, But I haven't done a breakdown cleaning in 3 months? So I just keep testing and changing 20% water when my ammonia levels get above 1.0, right? I'll get a NitrIte kit so I can keep a check on that too.
 
For a fishy cycle its 0.5ppm for ammonia and nitrites. Keep doing this until you have some nitrates. You can do a 20,30...80% water change. What ever it takes to bing it down And never do a break down! What kind of test kit are you using?

On a side not your tank is overstocked. What fish are currently in there?
 
Current population: 5 gal hex = 4 zebra danios, 1 small oto & 1 small gold snail

Test kits: Wardley - High Range Ph, Wardley - Jr. Ammonia & Aquarium Pharm. - NitrAte. Right now I don't have a NitrIte test, will get one in am.
 
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