This is green, so is algal growth rather than fungus. The ph of the compost can be a factor here plus keeping the surface too damp.

You could try a dusting of perlite or vermiculite after sowing. Very small seeds may need the covering slightly crushed to make it a little finer though the dampness is the main problem here.

i get this sometimes in growouse, i gently remove and add new composs which helps

thank you Fractal, i had an idea it may have been a damp problem but wanted to make sure it must be me watering too much thank you so much for your advice i will try the vermiculite..
hi san i am going to re pot and try vermiculiteand add new compost as you say thank you ...

also make sure you have ventilation as damp can be a factor

thank you Islander,i shall be taking all comments on board ..