Swapping Old Tank With New (& Moving Over Fish)

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Jul 19, 2005
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Kent, UK
Hi all,

I'm looking to replace my 180L with a 450L in the new year.

Problem is that the new tank will have to go where the current tank is, so what's the best/easiest/safest way to move the current stock of fish, and to swap the tanks/fish over? (I can swap over the external filter easily enough) Any help/advice appreciated.

Edited to say that I do have another 180L tank that I could put the fish into, but that would mean it would be very overstocked during the swap.

Thanks :good:
You have 2 180's according to your info, so i would think it would be simple to get a tank divider cut the other tank in half, move the fish, strip down the tank then put the new one in, get it running with the mature filter and then when ready move the fish back.

The other tank will be over stocked but it should be fine for limited time, just keep an eye on the water etc.

Shouldnt take more than 2-3 days

Option 2

This is one im lucky enough to be able to do, my Local aquarist shop will rent out tanks to regular people and maintain them while you move house, move tanks etc.
Brilliant - sounds a lot easier than I thought it might be - apart from filling a 450L tank :crazy:

I'll keep option 2 in mind as well as my lfs is always a great help.

Thanks :)
Ive done thisthe hard way....

Get a new filter and run that in the current tank.

Get some containers and the new heaters for new tank if your house is going to be cold or you are diong this alone (i do not recommend doing it alone!)...

Then.... on the big day.... this is what i did...

New tank sat on floor, clean and empty.

Transfer from old to new tank about 3/4 of the water (or more depends on size of old tank and how mucky it gets when you get down low and have loads of silt and plants to rip up)....

Transfer fish to new tank currently on floor, run heater and filter to keep it at right temp.

Empty out entirely, old tank, inc of substrate etc, give it a good wipe out. Put this on floor.

Start to shift water and then fish from new tank back to old tank, ditto filter n heater if poss.

New tank now empty, move into position vacated by old tank.

Put in new substrate (wash it!), plants etc, and slowly fill with warm new water.

Carry on filling with old water from old tank, put in heaters and A filter from old tank (remember you have two now), leave fish enough water in old tank .....

Put in fish or, if new tank very murky leave it an hour or so to settle and then upt them in.

Transfer last of water and other filter.

This ensures you have basically a cycled tank, when you are sure its ok you can remove the old filter if you wish to use it on teh old tank elsewhere. Running two filters on a newly set up tank isnt a bad plan especially if you have to shift the fish over straight away as it clears up any murkiness.

Ive done this TWICE now and whilst its a pain in teh rear of a job it gets it done in one day.

If you do have suitable containers and safe quieti places to put them to put the old tank water and fish into whilst you do the swap, do that instead, as its going to be less stressful - i didnt have either containers or a safe place (too many nosey dogs not enough safe rooms to shut them in) so did it this way.

Wow :blink:

I think someone should set up a professional company, in conjunction with the retailers, that does this for you for a fee - like when you have a new washing machine installed (I'd gladly pay) !
Put fish and filters (running) in your other 180, set up new tank, wait for water to heat up, move them back in. Should take 24 hours max, and the fish wont be overcrowded for long. ;)

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