betta clamped fins

Hi all, My tank is fully cycled, with ammonia 0.0, nitrite 0.0 and pH 7-8. Temperature is 26. I change about 20-25% of the water every week, using Tetra AquaSafe and Tetra SafeStart. The tank is planted with Anubias, Java Fern, Java Moss, Staurogyne Repens, Vallisneria Torta and RotaIa...