START-UP QUESTIONS

[capper]

This past Friday we put 4 small Cardinal Tetras in a new tank. The size of the tank is 30X30X25cm. We have a few plants (non o2 type) and an airstone as well. The tank has been used before but only shortly. It housed a couple of Corydoras Catfish and guppies. We also used it briefly as a quarantine tank. In other words, it has been used off and on briefly and is not "cycled" or at least not fully. I added some bacteria a few days before adding the 4 fish.

Anyway, here are my questions:

(1) When should we do our first water change -- and how much should we change?
(2) We have checked the water conditions twice since we added the fish (we checked for ph, ammonia, and nitrite). Everything seems good so far. Any advice as far as what to do with water params next?
(3) When would it be appropriate to start adding a few more fish (ie) algae eaters and maybe some guppies or danios?

One more unrelated question... I understand that changing the filter wool in aquariums is a big no-no because it can seriously change the water condition and harm the fish. However, if this is the case, what should one do with really dirty filter wool and contents? I have heard that you should rinse it out in water that was removed from your tank during a water change. When should one replace the filthy filter wool? What is recommended? It seems really dirty and needs to be replaced now and again? Suggestions?

Thanks in advance.

 

[FroggyFox]

OK first

1) I'd say do a 30% change now (a week in)...and then as soon as you start seeing the ammonia/nitrite rise you should start doing a small change every other day or as often as you see fit.

2) All you can do is wait...checking them is great. You might choose to do it every other day instead of every day until you start getting some readings above 0ppm on either test? You might also pick up a nitrate test and not worry about the pH. As long as your pH has held steady then you really dont need to test it much, its just important that it doesn't fluxuate much. With plants in the cycle you may or may not see any big spikes in ammonia/nitrite...but it depends on the type of plants/how many compared to the size of the tank and how well they're growing and absorbing nutrients out of the tank.

3) Until your tank is producing nitrate and has 0ppm of ammonia and nitrite (tank is cycled) I would not add any more fish. The only exception to that would be if 4 cardinals dont put a very big bioload on the tank...someone know how much water that size tank holds?? It doesn't sound too big.

As for the filter wool...yes, especially for the first say 3 months you definitely dont want to change that wool out. Rinse it all you want in dechlorinated water that you've either taken from the tank or is from the tap and dechlorinated and not too hot or too cold (to preserve the bacteria on the wool). I dont honestly change any of my filter pads out except maybe once or twice a year when they are actually so gross that they are impeding the flow of the water through the filter after just cleaning them a day or two ago. Then when its time to change them I'd try and leave both filter pads in there for awhile (say a week or so to give some bacteria a chance to transfer to the new pad) and then take the dirty one out and toss it.

Do you have any other tanks in the house? What kind of filter is on this one...I'd say if its a hang on back type filter the air pump/airstone aren't really needed.

 

[capper]

Thanks for your reply and great info. I am concerned that even in the small tank the 4 Cardinal Tetras are not enough for the cycling process to get going. Thus, I think it might be best to get a couple more fish -- perhaps a bit bigger. I was thinking of a couple of Platties or Mollies. Any advice on that?

Thanks again.

 

[CAPSLOCK]

The tank calculator on FishProfiles.com says ~6g (US), ~5 UK gallons, or 22.5 liters. That doesn't sound quite right to me though... I picture 30cm cube as maybe 2 gallons... but maybe my mental picturing is skewed.

I'd wait another week or 2 on more fish, just to make sure you aren't going to have an ammonia or nitrite spike. Platies are smaller than mollies, and breed more slowly, so they are a better choice in a small tank. If you don't want to breed, get all males because females are probably already pregnant. Otherwise, try for 2 females and a male so he doesn't pester one female all the time.

 

[discus4everGrl]

If it works out then great, if not-I would not suggest tetras for cycling a new tank. As the nitrites climb they will die.