# changing tropical fish tanks



## joanne87 (Mar 16, 2007)

hi all

i will be upgrading my tropical fish tank to a bigger one soon and wondered what i would have to do regarding the water cycle and the fish, i currently have guppies, mollys, shrimp, snails, albino catfish & sucking loach. Advise muchly appreciated.

thanks 
jo


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## LiamRatSnake (Jul 3, 2007)

Just use the same filter and run it alongside the new one for a while. Try to reuse the substrate and the water if possible and all should be fine.


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## WesternBlueTongue (Feb 12, 2012)

Shouldnt be too much of a problem. As long as some of the natural bacteria is replaced into the new tank then all should be good. If it is infeasible to run your old filter in the new tank, then allowing the new sponges to absorb some of the old bacteria is a good idea. Using the old substrate would be good too.


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## Railz (Oct 30, 2010)

unless the substrate is sand that has not been raked or stirred frequently


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## LiamRatSnake (Jul 3, 2007)

ridium said:


> unless the substrate is sand that has not been raked or stirred frequently


Very good point. No black sludge.


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## naughtyboy (May 27, 2012)

as said run with old filter in for a while, or run new filter in old tank.
i have always got couple of extra filters running across my various tanks one i use to go in q-tank if i get health probs.
also mens if main filter in tank breaks i can swap in ready matured filter straight away.
others are cos i never know when im getting extra tank cant resist bargain.


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