Thanks Christian n Jacob
It's the water that's green, the glass may be slightly green. It sounds as though the stocking rate is high but the fish are little more than 10mm long. The tank didn't start to go green until after the Fry stage, at least 10 days. The fish appear to be alert and healthy and the water parameters are all fine, it just looks bad. I thought it was probably a combination of excess food deposits and inadequate filtering but as a newby I'm not really sure.
Jacob, what do you mean by add heavy skimming and UV? Are you referring to a protein skimmer? What do you mean by UV?Also what is a bioball filter?
Gail (Newby Fish Keeper/Breeder)