what fish for this type of alge

I dont think there are many fish that will eat that hard stuff on the glass....just give it a good scrub

Neritina snails eat it. Its the only thing I have found that can scrape the small green spec algae off my glass.

Some plecos will eat that stuff up in no time! I moved one of mine to a plant/QT tank that had some pretty healthy thick green algae... emphasis on HAD. 2 days later barely a spec left, he even cleaned the leaves on a few plants!

i would try a pleco

If you do end up getting a magfloat, beware of any sand between it and the glass, it will scrape the crap out of the glass and is not very attractive, good luck!

Algae occurs for a reason. I suggest finding the cause of the algae and then correcting the imbalance before adding another animal which can compound the problem. Your algae has to have a food source and light source, like any other plant. The nutrients could come from overfeeding, lack of maintenance, heavy bioload, etc. Light, well, it's an obvious one, but does the tank receive any direct sunlight? What are your water parameters as of this moment. Also, if you have a phophate test that is reliable, that can help a bit in diagnosis as well.

At any rate, I cannot stress enough that adding an animal can make the situation worse, so I enoucrage you to dig a little deeper to fnid out just why the algae is growing.

Also, healthy plants will outcompete algae for nutrients, so it may be a simple matter of how you dose ferts or CO2 and lack thereof.