algae eating fish

is there any saltwater fish that will clean the tank and eat alage

 

Depends on the kind of algae.

 

looks like tiny green dots with green ferns growing of glass also brownish spots on glass

 

tangs will eat some kinds of algae. However, be sure that your tank is large enough to house these fish because they usually require a lot of space.

 

and and of the algae eaters often decide they dont want to.

 

You might want to get a picture up of that algae in the algae forum

is it a relatively young tank as the brown spots could be diatoms

IMO - snails and crabs are a better option for tank cleaning duties in salt water set ups
some fish may browse on certain algaes - dwarf angels , tangs etc
some fish specialise on eating algaes - lawnmower blenny ( problem is sometimes they are so specialised on eating this, and wont take other offerings so to keep them happy contented and well fed, you have an untidy tank

running GFO in a reactor or in a cannister filter to remove phosphates, combined with a decent CUC and caution as to how much you feed the inhabitants are better options than a fish IMO

Steve