Water Changes a plenty
I assume your tank is new but I may be wrong. Let me guess, you put a wholle lot of fish in right away while your tank was still new.
Algae is likely due to your high nitrates. Do water changes everyday of at least 40% your nitrites will kill your fish. I suspect your ammonia is also high.
For healthy fish keep ammonia at 0
nitrite at 0
nitrate at less than 20 for regular fish/ less than 15 for more sensitive species. You need to do more aggressive water changing at least in the short term to get your levels down.
Add a pre filter. If your using a power filter buy a filter sponge and cut a hole to snuggly fit it over your filter intake,(the tube that extends down into the aquarium). Feed less at least untill you get the nitrite under control.
I have to say again your nitrite is at scary levels you have to get it under control. Something I just learned on this site, adding a little salt (e.g.1/8 tsp per gallon), helps reduce nitrite toxicity in fishes blood. Get aquarium salt-(non iodized sea salt works too).