I'm more inclined to think it's an algae, but it doesn't matter, as my suggestion to deal with it is much the same.
Reduce the light photoperiod, you can go down to six with no trouble, do it an hour at a time and give it a week or two to see results before further reduction. The intensity of the light may be a factor, but lets try other easier fixes to avoid new lighting. But, can you reduce the intensity? Some LED lights have this feature.
On the nutrient side, these plants need nutrients. With only two fish, they need supplemental fertilizer. I would first start with substrate tabs, and Seachem's Flourish Tabs are about the best; they do not leech into the upper water column so they cannot feed algae/cyano. Liquid fertilizer will be needed for fast growing non-substrate rooted plants, like the floaters. Flourish Comprehensive Supplement is one, if you are in the US there is also Brightwell Aquatics MultiFlorin. Be sparing in using this. What is the GH (this is a primary source of calcium and magnesium)?
A definite recommendation...floating plants. Really, good floaters have an almost unlimited array of benefits for an aquarium, and here a major one is their shading the light and using a lot of nutrients so this will help avoid over-fertilizing. Water Sprite, Water Lettuce, Frogbit; some stem plants do very well floating, like Pennywort.
