Help Please! Turning My Tropical Tank In To A Coldwater One.

[HippoHen]

Hey there although not new to the hobby I have a question that perhaps is bet suited to this section of the forum.

Anyway I currently have a large 3 foot tank that is currently only housing some zebra snails, 6 harlequins and a few phantom tetras. Anyway I have a real desire to have a really heavily planted tank but I don't believe this current tank to be suitable as I feel it is a bit too large for my first heavy planted tank and also the lighting on it is pretty poor. So i am wanting to downgrade to a smaller tank. Fortunately I have a smaller tank that has 2 fantails in it. So the plan that I have now is to swap the fish round. If I left the current filter in the tropical tank but took the heater out, would after a day or so when the water has become room temp be able to put some fantails in it? Also does this work the other way round?

Many thanks for reading

 

[ReddSamurai]

zebra snails are temperate as far as i know so they can go in either.
hmm thats going to be difficult, the only thing i can think of would be to bag all the fish up then do like a 30% water change but when topping up the tanks put slightly colder/warmer water in depending what tank your topping up just to give the temperature a boost, and then float the bags for an extra half hour to give it time to acclimatize.
 
this is all i could think of   

 

[Livewire88]

The way I would do the change is to remove the fantails and put them in a decent size bucket of their tank water, remove the heater from your large tank and put it in the smaller tank and top it back up with warm/hot water, in the time it takes the heater to heat the smaller tank up to the desired temperature the water in your other tank should not drop so low that it effects the fish. 
 
Then swap the fish to over to the smaller tank, by then the temperature in the larger tank should be fine to put the goldfish in but if it is still a little high just change some of the water with cold water to bring it down. 

 

[HippoHen]

Thanks for the advice. So no need to worry about swapping filters as long as the tempetature changes slowly?

 

[HippoHen]

So would the filters be ok?

 

[ReddSamurai]

yea the filters should be fine, they will be doing the same job in either tank... breaking down the ammonia,nitrite and nitrates etc