There are a few things to consider before installing a filter.
1. Tank size – if your tank is under three gallons, filters should not be installed under any circumstances. The disturbance from the current will tear your Betta’s fins and cause him undue stress.
2. Betta’s sex – females can generally tolerate air currents much better because of their small fins.
3. Type of filter – power filters and under-gravel filters should not be used in tanks under 10 gallons. Small filters with adjustable current are much better tolerated if set to the lowest current.
4. Individual Betta – if you’ve had more than one Betta, you know that Bettas tend to have very individual personalities. Some fish will thrive in filtered tanks, while others become sick. Observe your Betta very closely after the installation of the filter – look for signs of fin rot, lethargy or swim bladder problems; if you see any abnormalities, take the filter out immediately.
