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Fish/A few things regarding my 3 week old cage and new fish


I have a 3 week old, 10 gallon tank that has a functioning filter and a functioning heater that is set to 77 Fahrenheit for my tropical fish. The tap water used to fill the tank has been treated with the correct amount of "Aqua Safe Plus," (5 ml). I let the heater and filter run for two days before adding my first fish. My first fish was a glow fish and it swam up and down the glass for a large amount of time on the first day that I had it in my tank. I tried feeding it several hours after I had put it in the tank but it didn't eat any. After that day, it didn't move much at all and still refused to eat. It died the day after that. I didn't change the water after that because I figured that it died because the bacterial part of the filter hadn't started yet and I figured there was no point in cleaning the cage because there was only two days worth of food at the bottom of the tank. About three days after that fish's death, I got a cory catfish and it has been living in my tank for about two weeks. About two days after I put it in my tank, the tank clouded up extremely badly but I didn't worry too much because I had heard that it usually happens when the bacteria from the filter starts working. The heavy cloudiness of the tank disappeared in about two days but it remained slightly cloudy. After about a week I cleaned out the tank and changed about 50% of the old water with treated water of about the same temperature. The cloudiness lessened greatly but continued, along with a strange smell. My catfish was doing fine for a while so i introduced two more fish in to my tank. The problem is that my catfish has started to rarely move at all, even for a catfish, and the two new fish have been eating but they have also been swimming up and down the glass for very long periods of time like my glow fish did, and of course there is a slight cloudiness as well as an odd smell coming from the tank. I am planning on doing a complete water change very soon but I was hoping you could shed some light on what is happening with my cage and my fish

Hi Braden

A glow fish in a 10 gallon tank by itself, would not have died in 3 days due to new tank syndrome. The glow fish died due to stress, not a problem with the tank. They are a schooling fish and do not do well as singles, especially when taken from a tank with tank mates and put into a strange tank by themselves. It is quite normal for new fish (all species) to swim up and down the glass when put into a new tank. Also, always wait at least 24-48 hours after introducing your fish to a new tank to feed them. During this time, they are stressed, checking out the new environment and not thinking about eating. So any food you put in the tank will fall to the bottom and become waste. This waste causes your ammonia to spike.

The cloudiness and smell are common when a tank is cycling, the smaller the tank, the more noticeable this is. However you should not have introduced more fish. The Cory Cat would've cycled the tank just fine in a couple of more weeks. Adding more fish before it was cycled, created more of a bio-load on your tank and filter than it was prepared to handle.

Do NOT do a complete water change!! This is a common mistake among new tank owners. You will destroy all the progress the tank has made and cause it to start over. Do a 25% water change, and siphon the surface of the gravel to remove surface waste. Do not go deep into the gravel until the tank has completed its cycle. Change the carbon in your filter. Then wait 24 hours and check your levels. If they are high, do another 10% - 15% water change. Again check your water parameters after 24 hours. At this point you should be fine doing a weekly 25% water change.

Finally, raise the temp in your tank to about 80. 77 is fine, but may be a little cool for a Cory.

Hope this helps, good luck!



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Richard Hight


I own and maintain several freshwater aquariums from 2 to 180 gallon. I can answer most questions about freshwater aquariums, including setup, cycling, maintenance, compatible tank mates, feeding. Moving? I've moved fish both across town and across the country and can help you get your little aquatic friends to their new home safely. I know and have experience with most freshwater community fish, South American Cichlids and African Cichlids. I don't answer questions about Goldfish or keeping Goldfish with Tropical Fish. I also don't answer questions about keeping crustaceans (shrimp, snails, crabs etc) with Tropical Fish, nor questions about saltwater fish or aquariums. I'm not available to answer questions on weekends, this is when I do maintenance on my own tanks.


Many years of personal experience with fish and aquariums

HSG 2010-2011 prof

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