# Help "resetting" tank for new fish



## jeffnc (Oct 30, 2010)

I had 4 goldfish in a 15 gal aquarium that died from some disease/infection. Please see this thread
http://www.aquariumforum.com/f5/help-ich-progress-11263.html

We're now ready to move on to new species - freshwater tropical. We have a heater and good filter in there. What I need to know now is how to transition the tank to prepare for the new fish. I of course don't any trace of the old bacteria or whatever in the tank, but at the same time I'd like it to be "cycled" if possible.


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## Gizmo (Dec 6, 2010)

The best thing to do right now is just run the tank like you would if you had fish in there, and add some fish food or straight ammonia. This will provide a source of ammonia to establish the nitrogen cycle up. To speed things along, buy a bottle of Tetra SafeStart or some API Stress Zyme and dose your tank with it. These "tank starters" contain bacteria cultures that will colonize your tank to process the ammonia. Wait a few weeks, take a sample of water to your pet store and have them test it. If after 2-3 weeks you have zero ammonia, zero nitrite, and some nitrate (even with adding a source of ammonia), you should do 1-2 50% partial water changes to lower the nitrates, then you may add fish.

All of the bacteria that might have killed your goldies, without a source to infect, will starve and die before you add any new fish.


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## susankat (Nov 15, 2008)

I think with the issues you had with the goldfish I would clean everything real good and start all over and doing a regular cycle. Just leaving it sit for awhile with same gravel and filters will not rid the tank of what was in it. There is some diseases that can hang around for months in an empty tank.

Personally if it was my tank I would strip it down, bleach the tank, rinse real well, then rinse again. Fill with water add dechlorinator, let sit for a couple of hours then empty and rinse again. Add new substrate. And clean the filter good and add new media, then cycle the tank.


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## NeonShark666 (Dec 13, 2010)

If your old tank is running, keep it running (good cycling bacteria still there). Run good filtration with carbon in your filter pads, changing them frequently, and have some good aeriation. Make sure your temp is 72-75 and add two White Mountain Clouds or Guppies and start cycling. Add some floating plants and some rooting plants (Vall, Java Fern), they help to reduce the Ammonia spike. If you can, test for Nitrates. If high, change out about 30% of your water and make another change in a few days. If your tank is no longer running, take it outside and wash it out, including the gravel. If you want to disinfect the tank, use a saturated salt solution but don't water your plants with it. Keep the old gravel if you want, and start over again.


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## snail (Aug 6, 2010)

I normally say not to restart a tank but in this case I think I would if it was me. Most infections (like ich) can be gotten rid of by letting the tank run without fish but those goldfish looked really bad and had multiple unknown problems. It's a fairly small risk but there are some diseases that might stay in the tank so I'd follow susankats advice on cleaning the tank, then do a 'fishless cycle'. If you decide not to restart leave the tank for plenty of time before you add new fish.


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## jrman83 (Jul 9, 2010)

Completely re-doing it all would be a pain, but all you'd be losing is a little time and some beneficial bacteria. The tank may have been close to completing the cycle, but if you don't re-do and start having issues again you'll hate yourself for not doing it. Now is the time to do it. I guess I could understand if you didn't though, it will be a little work. If you decide not to, at least do a near 100% water change, filter clean, and then crank your temp as high as your heater will take it and hold for at least 10 days. At least that should take care of any ich.

Sorry for your luck. We've all been there to some level.


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## J-Pond (Jun 8, 2009)

With the fact that you were WAY OVER stocked (4 goldies in a 15gallon) and they had ich, I would absolutley break down the whole set up. As stated above, clean it with bleach 10:1 ratio, rinse it very good then re-wash with white vinegar and hot water and rinse again, then rinse with just hot water. Then you can feel safe about restarting the tank.


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