Can I cycle my bettas 2.5 gal tank?

Question
QUESTION: Hi.  I'm rather new to aquarium keeping.  Here is my question.  I recently got a 2.5 gallon minibow aquarium and due to no other housing available for my betta, I had to put him in the new 2.5 gallon aquarium immediately upon purchasing him.  I know that it is preferable to cycle your tank without fish but, unfortunately, that is not an option for me.  The tank has a filter running in it currently.  Can I cycle a tank this small?  How often should I perform partial water changes on a filtered tank this size?  Should I ever perform a complete water change on a filtered tank this size?  Also, how often should I change the filter cartridge in my filter?  I thought that the filter cartridges harbor good bacteria that you actually want in your aquarium so why would you ever want to change the filter?  (Sorry for so many questions but I already lost one betta to dropsy and am trying to do everything right with this 2nd little guy!)

ANSWER: Hello Connie. You can cycle a tank that is small. Some 2.5 gallon tanks come with filters, and some people just buy them separate. Every two weeks, or so, do a 20% water change. When you perform a complete water change, it should be either because of the fish being sick, or there is another problem, such as fungus. The filter cartridge should be changed once a month or so. You need to change the filter, because inside the filter is all those little bacteria, food, any type of fungus that gets stuck in there. You don't want a dirty filter, filtering your water right? So make sure you do change that filter, I remember I made the mistake of forgetting to do that. My tank ended up getting covered in green slim, and so did the filter. It was a mess. Good luck with your 2nd little one!

Alejandra

---------- FOLLOW-UP ----------

QUESTION: Thank you for your answer.  Just to confirm, doing a 20% water change every other week is sufficient to cycle the tank with a fish in it?  Don't I need to worry about the ammonia levels rising to much?  Thank you for your time.

Answer
Since you have a filter in the tank, you don't need to change the water every week, unless you want too. If your worried about the ammonia levels, go ahead and change the water once a week. But I wouldn't be so worried about the ammonia levels so much. You will be fine. Just don't overfeed, and the ammonia levels wont go up.

Alejandra