Sorry for the lengthy post but I want to fully describe what has happened in the hope that someone can help me.
I have had my 29 gallon cycled and fully stocked for over a month now. I'm using a Aquaclear 300. The temperature has been a very steady 77F. I am using only plastic plants. I have been stocked with 3 swordtails, 6 zebra danios, 2 dwarf gouramis (male and female) and 4 corys. As I said the tank has been cycled and these fish have all been living happily for the last month.
I have been doing weekly water changes of 5 gallons. My ammonia levels have been 0, nitrites 0, nitrates between 5 and 10ppm, kH equal to about 5 dkH. Finally pH has been a bit high but completely steady at 8.0. My tapwater pH is high thus the high pH. But the advice I've gotten is that better a bit high pH than one that is changing all the time.
Anyway, I started to see some brown algae growth a few weeks ago. I have been very careful with feeding so I expected overfeeding was not a problem. I did read that too little light could be a cause. I had been using the stock fixture that came with the tank thus getting 20W over the 29 gallon. It seemed this was low so I upgraded to a new fixture and now have 40W over the tank. That was about a week and a half ago.
At the same time I decided to get a few Ottos to help clean up. I know the stocking is a bit heavy but water values have all been low and I have been keeping up with water changes. Anyway, last Thursday I got 3 ottos. I brought them home and slowly aclimated them using the drip method over an hour plus, just like all my other fish. I added them to the tank. By Friday night one was dead, and by Saturday the second was dead. I know these are very fragile fish but still these were the first fish I had lost. The third otto is still alive and looking good.
Finally getting to the point of the post: I came home tonight to find one of the cories on his side at the bottom of the tank spasming. He would flop around for a bit then stop, settle back to the bottom and breath very heavy on his side. This repeated for awhile until I finally removed him from the tank.
I retested all water parameters and everything was the same as it has been except for my pH which went up to about 8.3.
The pH in my tank has been the main thing that is confusing me. I have been doing water changes for about two months with a mix of spring water and tap water. My tap water is 8.0 and the mixture I put into the tank tests at 7.6. I was hoping to bring the pH of the tank down over time by mixing in the spring water. I let the mixed water sit for a week before using it. Like I said it always has pH around 7.6 and 5 dkH as well. Anyway with all this my pH is somehow going up. I am confused. With the last water change I also removed a rock from the tank that had been there since setup. It is light in color and I bought it from the LFS, tank safe. It thought maybe this was the reason the pH was staying high, it acting as a buffer, thus i removed it. Perhaps this could be the reason the pH went from a steady 8.0 to 8.3 over the last two days. Anyway I'm still unclear how adding water with pH 7.6 and 5dKh over two months can result in the tank still having pH of 8.0.
I guess overall I'm hoping someone can shed some light on why my Cory died. I don't want to lose anymore fish. As of yesterday they all looked fine, everyone had been out and active, good color, everyone got excited at feeding time etc. I guess I'm just at a loss. Again sorry for the lengthy post and thanks for any help.
I have had my 29 gallon cycled and fully stocked for over a month now. I'm using a Aquaclear 300. The temperature has been a very steady 77F. I am using only plastic plants. I have been stocked with 3 swordtails, 6 zebra danios, 2 dwarf gouramis (male and female) and 4 corys. As I said the tank has been cycled and these fish have all been living happily for the last month.
I have been doing weekly water changes of 5 gallons. My ammonia levels have been 0, nitrites 0, nitrates between 5 and 10ppm, kH equal to about 5 dkH. Finally pH has been a bit high but completely steady at 8.0. My tapwater pH is high thus the high pH. But the advice I've gotten is that better a bit high pH than one that is changing all the time.
Anyway, I started to see some brown algae growth a few weeks ago. I have been very careful with feeding so I expected overfeeding was not a problem. I did read that too little light could be a cause. I had been using the stock fixture that came with the tank thus getting 20W over the 29 gallon. It seemed this was low so I upgraded to a new fixture and now have 40W over the tank. That was about a week and a half ago.
At the same time I decided to get a few Ottos to help clean up. I know the stocking is a bit heavy but water values have all been low and I have been keeping up with water changes. Anyway, last Thursday I got 3 ottos. I brought them home and slowly aclimated them using the drip method over an hour plus, just like all my other fish. I added them to the tank. By Friday night one was dead, and by Saturday the second was dead. I know these are very fragile fish but still these were the first fish I had lost. The third otto is still alive and looking good.
Finally getting to the point of the post: I came home tonight to find one of the cories on his side at the bottom of the tank spasming. He would flop around for a bit then stop, settle back to the bottom and breath very heavy on his side. This repeated for awhile until I finally removed him from the tank.
I retested all water parameters and everything was the same as it has been except for my pH which went up to about 8.3.
The pH in my tank has been the main thing that is confusing me. I have been doing water changes for about two months with a mix of spring water and tap water. My tap water is 8.0 and the mixture I put into the tank tests at 7.6. I was hoping to bring the pH of the tank down over time by mixing in the spring water. I let the mixed water sit for a week before using it. Like I said it always has pH around 7.6 and 5 dkH as well. Anyway with all this my pH is somehow going up. I am confused. With the last water change I also removed a rock from the tank that had been there since setup. It is light in color and I bought it from the LFS, tank safe. It thought maybe this was the reason the pH was staying high, it acting as a buffer, thus i removed it. Perhaps this could be the reason the pH went from a steady 8.0 to 8.3 over the last two days. Anyway I'm still unclear how adding water with pH 7.6 and 5dKh over two months can result in the tank still having pH of 8.0.
I guess overall I'm hoping someone can shed some light on why my Cory died. I don't want to lose anymore fish. As of yesterday they all looked fine, everyone had been out and active, good color, everyone got excited at feeding time etc. I guess I'm just at a loss. Again sorry for the lengthy post and thanks for any help.
