Tint Little Worms Things In My Tank

[newtothis26]

i have a 90 ltr tank with sand substrate at the bottom 2 plants and few decorations i have done 2 50% water changes to day and iv noticed them in the tank i want to what are they as i have 4 female guppies waiting to go in there and want to no if they are safe please does anyone no

 

[ellena]

Are they tiny and white and on the glass? Could be planaria. Their population grows if there is ammonia in the tank. So keeping stats under control will normally get rid of them. They can get into fishes' gill and irritate them and you can use a med called sterazin to get rid of them too.
I take it you have no fish in the tank atm? If so, why are you doing water changes?
Have you cycled the filter?