Transferring betta to bigger tank - Would this idea work?

I have a betta in a 3.5 gallon and want to move him into something at least 10 gallon. Could I move all the substrate, plants, decorations, filter media, etc. and the water that's currently in the 3.5 gallon into a 10 gallon, fill the rest with conditioned water (with a teaspoon or so of beneficial bacteria) and move the betta in same day? If I go with a larger than 10 gallon tank I'll probably get some tetras and/or corys or something as well and use the 3.5 gallon as a quarantine tank.

 

it should work, just monitor your parameters closely. And Corys do not belong in a 10 gal

 

If you just do a 10 gallon then it should work, any larger and it could have a tiny bit of a ammonia spike but it should be fine either way

 

it should work, just monitor your parameters closely. And Corys do not belong in a 10 gal

I wouldn't put corys in anything smaller than a 20 gallon...probably 40 gallon minimum. It just all depends on what I decide to do.

 

With no increase in bioload the bacteria colony you have will deal with the fish waiste of the fish you have now no matter how large of a tank you go with.

 

Just add new fish slowly so the bacteria colony has time to adjust to the increasing bioload - in a way, every time you increase the bioload you have sort a "mini-cycle" taking place in the tank, so take that into account and monitor parameters and do water changes as needed. With regards to moving just the betta only, everything should be just fine.