What filter characteristics help protect delicate fins in a betta tank?
A betta-friendly filter keeps water movement slow and even so that long fins are not pushed around. Quiet operation and a model that's the right size for your tank help maintain a calm environment. Focus on filtration that keeps water clean without prioritizing brute power since balance matters more than speed for these fish.
Can a hang-on-back filter work for a small betta tank without causing too much current?
Yes, as long as the filter offers a low, adjustable flow and is rated for smaller aquariums. Keep the movement gentle to avoid stressing your fish, and choose a design that works quietly. If the current still feels strong, an internal or sponge style filter may be a better fit for a small setup.