Why are my fish dying?

**cj5_dude** · 12-09-2012, 12:59 AM

I have a 29 gallon tank with 11 cardinal tetra's, 1 dwarf gourami, 1 common pleco, and I did have 5 julii cats. Now I'm down to 2 cory's. I did a water change a few days ago and I'm surely not overstocked. This tank has been running for 2 months with no problem after a fishless cycle. All of the other fish are doing fine but the cory's are dying off, and all rather suddenly. I lost the first about a week ago and found it dead on the bottom, then a few days later found another. I then did a water change and today found a third dead.

I've got quite a bit of brown algae growing on the fake plants, mostly under the lighting.

What's the problem with the dying fish?

**Honey Badger 1** · 12-09-2012, 01:09 AM

Before we can help we need to know your water parameters, what are the ammonia, nitrite, and nitrate levels?
Brown algae is most likely diatoms and are common in a new tank, once the nutrients they need, usually silicates, once the tank matures and balances itself out, they will die off, just keep cleaning them off and removing them with water changes.
The common pleco will quickly outgrow your tank.

**Lady Hobbs** · 12-09-2012, 02:11 AM

Your tank may have been cycled but you lost the cycle somehow. Have you recently cleaned out the filter media or perhaps forgotten to use de-chlorinator?

**cj5_dude** · 12-09-2012, 02:38 AM

My ammonia, nitrite, and nitrate are all at 0. I cleaned out the back of the filter and gently rinsed the sponge filter media but didn't touch the ceramic bio media.

**cj5_dude** · 12-09-2012, 02:40 AM

And I live on well water that isn't chlorinated so I have never used dechlorinator. It seems the only fish this is affecting are the cory's.

**KevinVA** · 12-09-2012, 02:52 AM

Your parameters suggest you haven't cycled, since you also have 0 nitrates. Rinsing the sponge could have killed quite a bit of bacteria, as well, since they take up residency in sponges, in addition to the bio media. It's possible you're undergoing a mini-cycle, because you lost some.

Corys are bottom grazers. It's typically suggested that they be added to the tank after it's established, usually several months from the point you started adding fish. It's possible that as you've been adding fish, the increase in ammonia (in the process of building more bacteria) could have been too much for them, as the most toxic water is at the bottom of the tank.

**Goes to 11!** · 12-09-2012, 03:05 AM

Kevin his water is not chlorinated though possibly something else is going on to affect his cycle.

I also see having 0 TrAtes as a sign that your tank is not fully cycled, 0 TrATes typically requires a lightly stocked & heavily planted tank to achieve.

Was that test taken before or after your water change? [& what is your routine wrt WC - What % & how often?]

What are you testing with & What PPM of ammonia did you cycle your tank with?

**KevinVA** · 12-09-2012, 03:11 AM

Originally Posted by 850R

Kevin his water is not chlorinated though possibly something else is going on to affect his cycle.

I also see having 0 TrAtes as a sign that your tank is not fully cycled, 0 TrATes typically requires a lightly stocked & heavily planted tank to achieve.

Was that test taken before or after your water change? [& what is your routine wrt WC - What % & how often?]

What are you testing with & What PPM of ammonia did you cycle your tank with?

It may not be chlorinated, but if he rinsed it with water too hot or too cold, it could have killed some bacteria.

**Honey Badger 1** · 12-09-2012, 03:25 AM

It takes temperatures of 32 degrees Fahrenheit and 120 degrees Fahrenheit to kill nitrifying bacteria. I doubt he used water that cold or hot. Optimal range is 77-86 degrees Fahrenheit, and anything below or above will slow down growth, but unless he used ice, or water too hot for comfort he didn't kill any off.
http://onedersave.com/blog/497/take-...-the-aquarium/

**cj5_dude** · 12-09-2012, 03:48 AM

Originally Posted by 850R

Kevin his water is not chlorinated though possibly something else is going on to affect his cycle.

I also see having 0 TrAtes as a sign that your tank is not fully cycled, 0 TrATes typically requires a lightly stocked & heavily planted tank to achieve.

Was that test taken before or after your water change? [& what is your routine wrt WC - What % & how often?]

What are you testing with & What PPM of ammonia did you cycle your tank with?

The test was taken a day or more after the last water change. I routinely do a 10% water change every 2 weeks. I originally did a fishless cycle with a 4ppm ammonia reading. My filter is an Aquaclear 110 so it has a very large surface area to house the nitrifying bacteria for a 29 gallon tank. I'm testing with the API drops kit.

I most definately have completed a cycle, although I won't rule out that I somehow started a mini cycle. The water used to rinse the sponge was around 80 degrees. And the rinsing process was filling a bucket with freshwater and gently shaking the sponge out in it.