Fry tank you want to clean more than once a week..
Some algae you don't want in there.. but if it's the common green one then you shouldn't have too much of an issue. Some breeders do not want it at all.. as I know some are bad for the fry.
I would suggest getting a couple mystery snails or pond snails to help get rid of it. Otherwise I would suggest wiping it off as much as you can.
How long do you keep your lights on in the tank?
I would not keep the lights on for more than 8-12 hrs a day, and live plants will help keep the algae down as it will compete for the nourishment, etc and usually the plants will win. I keep a good amount of plants in my fry/grow out tanks along with a snail or (in the grow outs) the 4" bristlenose plecos and have yet to have any algae. Also only keep the lights on for 10-12hrs at the most.