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Can I quick-cycle a new tank w/ cycled water/filter?

775 views 2 replies 2 participants last post by  likealostpuppy 
#1 ·
jaysee, I have a Q for you (and anyone else who has input): I just started a second 38-gallon tank with new aquarium sand. First I rinsed the sand in the tank with tap water, then I added about 13 gallons of water from my cycled tank, and then I filled it to about 36 gallons with tap water and added enough stress coat (it's similar to prime) to dechlorinated the tap water. I put the used filter from the other tank in the new power filter and left it running for 24 hours. Then I added 3 small feeder fish, but they were all dead when I looked 4-5 hours later. I thought hard about what could have possibly gone wrong and I realized I did not dechlorinate the tap water that I was unable to pump out after rinsing the sand, so I added more stress coat to it for the amount of water that I had missed. Two more days went by, just letting the filter run. Then today I put 4 small rosy reds in and they are still alive. Do you have any idea when the tank should be ready for more fish? I'm anxious to put my fire eel in there but I don't want to kill him. He's fine where he is for now so there's no true hurry. Thanks!
 
#2 ·
Feeder fish are notorious for inexplicably dying, so I wouldn't lose any sleep over that.

Transferring established media to your new tanks filter is unquestionably the best way to start a new tank, as it becomes ready for fish immediately. Caution - that's how many of us went from 1-2 tanks to 10 :)

How many fish? That all depends on the amount of media you moved, and what the bioload of the old tank was. For example, if your old tank had 3 goldfish in it, and you moved all of the media into the new filter, you could support those same 3 goldfish in the new tank. Of course the bacteria in the substrate was not transferred so it could take a couple days to balance out.

The beneficial bacteria colonies are among the slowest growing there is - they double about every 24 hours. So, if the bioload of the eel isn't more than the other fish already in the tank, you can add it without any issue. One word of caution there - in a brand new tank, the biofilm has to first form before the bacteria can attach to the surfaces, so if you are too quick about it it's possible to have an issue. So without knowing the size of the fish in question, it's hard to say for sure what the expected outcome should be. If the fire eel is significantly larger than the combination of all the other fish, then you've got a little work to do. You can start prepping the tank for it's arrival by overfeeding for a period of time. That will build up the bacteria colony. May or may not be enough, but its something and it'll cut down on your mini cycle. Mini cycle is what we call it when an established bacteria colony is overmatched. Excess ammonia remains in the water until the ammonia bacteria has sufficiently grown, at which point there will be excess nitrite in the water until the nitrite bacteria has grown. That all will typically be sorted out with a week.

Now you have some control - you can stop feeding after you've introduced new fish. Feeding will only add to workload of the bacteria, so by stopping you are giving the bacteria a chance to stay caught up in the transition.

For future reference, unless you have to alter your waters chemistry, you don't need to transfer any water to a new tank. There's nothing in the old water that will help you.

Oh and I'm sure you already know this, but make sure the top is completely covered, cause those eels are notorious for jumping out even the smallest holes.
 
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#3 ·
Thanks jaysee :) I just read this. For some reason I was not notified that you had replied to my thread but I had other post notifications. Anyway, I still have just goldfish in there, but now there are about 6 small ones and one really big one that somehow eluded my gar for over a month in the big tank. He had marks/scales missing from where the gar had grabbed him but he has recovered so I guess he'll have to go back to the store eventually lol. Anyway, I think the tank is ready as far as the cycle goes. I was unaware of the "bioload" science and I also didn't know the water from an old tank would be of no use, so you taught me something new :) Now I need to get a nice pleco to go in with the fire eel. I've been looking at snowballs and gold nuggets but they are expensive and I will have it for a long time, so I need to be sure I really want what I pick.
Thanks again,
Sally
 
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