Threadfin Rainbows & Planted Tank

My tank is Algae Soup. Fact.
Everything covered in slimy green web like Algae. A total mess. I need to
start over this weekend. There are a number of things I recognise that I
have done wrong. One of them is that my fishload is very low, thus providing
practically zero nitrates or phosphates for the plants! It is a small 10
gallon tank that only houses 4 Threadfin Rainbows. I would like to add some
more peaceful compatible tankmates. Any suggestions? Quantity? Species? I
can't add more Threadfins as they are rare in my area and I bought the last
4 from the LFS, 1 male (he's a beauty) and 3 females. Any Ideas?

Many Thanks
Cameron