Upgrading tank - transfer equipment, keep fish alive...

[SwerveDriver]

I'm considering upgrading my 15 gal to a 40 - 50 gal tank some time soon. I made a mistake buying the smaller tank. It just seemed big enough empty, but when you add decoration, filters, heaters and the fish it doesn't seem so roomy any more.

Well, here's my dilemma. I have a Emperor 280, 100W heater, and 6 Harlequin Rasbora's. I had my tank cycled before adding the fish. The aqurarium has been up and running for two week now (one week with the fish). I plan on using the filter and heater for my new tank, so how should I go about getting the 40 gal ready and cycled, while at the same time keeping my Rasbora's alive in the 15 gal when I transfer the equipment?

Should I just transplant the gravel and water into the 40 gal and run the filter? Then slowly add water every now and then to fill it up, while testing the water?

 

[Fishboy-from-NY]

You got it, the I would first add the new gravel in the new tank then layer it with the old gravel which has the benifical bacteria. Then, all the water from your old tank add that in it to, then make sure you get a product called Bio-Spira, it's a bacteria additive which helps speed the cycling up fast(GREAT STUFF). After make sure you water that you placed in the tank, matches the same water parameters as the old water. AFTER THAT YOU SOULD BE GOOD.

 

[poikilotherm]

Since the bioload will initially be the same in the larger tank as in the smaller tank, you should be able to just move the gravel over (vac it first!) and move the filter over and move the fish in right away.

Some may say this is risky, but I can't see why you'd need to cycle the larger tank when you're moving the filter and gravel over with all the bacteria you need right there! The one trick is to get the water the same in both tanks (temperature, pH, hardness, etc), you could exchange water between tanks over a day to make sure.