Setting Up Filter

[totrav]

I have 1 betta in a 2.5 gallon tank. It came with a filter and I am thinking about setting it up. Do I have to do a fishless cycling or can my betta be in from the start?
Also, if I do use my filter should I do a water change before setting it up? Or keep the old water in to start off the filter?

 

[fishlover500]

Because with bettas they usually don't have a filter anyways you can just do a fish cycle as your water will already have ammonia and it won't make a diffference. About water changes: you can do water changes with it running or without it, so long as once the filter has cycled it stays wet, and has water flowing through the filter media, although it can go for a while without water flowing through it.

 

[OldMan47]

Welcome to the forum Totrav.
Since you already have the betta and are looking after it without a filter, a fish-in cycle makes sense. Just maintain the betta's water the way you always did and monitor the water right before your routine changes. You will find after a while, probably several weeks, that you no longer need to change water quite as often or quite as much each time. At that point your filter will be cycled for the single fish that you have.