Filter or No Filter

[Gwenn32]

I own four betta fish. A four year old male who is doing just fine, and three females who share a decent sized tank. I have never used a filter with my male, so I figured that I wouldn't need one for the females. Am I right or wrong to do that? Some people have told me that even bettas need a filter, but I can't really say I agree because of my male. Now, I'm wondering if I could put any other fish in the same tank as the females. Depending on your opinion of the use of a filter, are there any fish I could put in? My females have hardly ever been agressive towards each other, so I assume they would be fine with a tankmate. My major question is are there any fish other than bettas that don't require a filter to survive and be healthy?

[Tikibirds]

It depends on the size of the tank. Without a filter - you should be doing a 100% water change and a 50% every week. It's not bad for 5 gal and under but anything bigger and its more of a hassle then anything else. With a filter. if the tank is over 5 gallons and one it completes the nitrogen cycle - then you only need to do maybe a 25% water change a week.

How big is the tank with the girls? It should be no smaller then 10 gallons and ideally there should be 5 females. You want to have 4 or 5 because that will spread out the aggression between them so the same one won't get picked on all the time. I seldom see any fighting with my females but I know some people have issues with their girls fighting alot.

Of course, the bigger the tank the more options you have for tank mates. Some species are more sensitive to water chemistry and you should have a filtered/cycled tank before adding them. Some do better in hard water, some in soft water and some just shouldn' be with bettas as they won't get along.

[Myates]

I agree with Tiki 100% - 10 gallons or larger, more females.. even though they have been getting along, at some point two of those females will gang up on the smallest/weakest one and kill her, then they go after each other. More females is needed to spread out the aggression. Females can be just as aggressive as males, and most sororities tend to have issues at some point.

Since the tank has to be bigger and you want another type of fish added in, you should have a filter.. most other fish will need a good cycle and the aeration brought on by the filter.

[Gwenn32]

I have a 10g

[Gwenn32]

Lets say I bought a filter, does anybody know what fish could be acceptable?

[Myates]

Well, add in 1 or 2 more female bettas (make sure the tank is heavily heavily planted with fake or real plants.. that reach middle and top of the water.. rearrange tank when adding in new females otherwise the new ones will be attacked).. after that, can add in a few cories or a few platies/swordtails.

Here is the link to the section about stocking tanks with bettas. Females can be grouchy, but they don't have the long flowing fins such as males so you have a bit more options as to what to place in with them. Here is a guide that may also be useful.