White droppings.......platies' not bat's

yesterday i found my platies n swordtails dropping white stuff. is it normal? i've seen black or brownish usually. but white was quite surprising to me.

i think there was some infection in the water. coz, they have been hiding in corners n swimming jerkily. i've treated the water with salt. and everything is fine now. except for the white droppings.

does anyone know abt it ?????

i've read that feeding tubifex causes white droppings sometimes. has anyone noticed that before ??

hey thx for the reply. alls perfect now. i gave them salt baths every alternate day. and added sme methelyne blue. they r very much fit now. and i've moved them frm 10g to 40g