Sera Shrimp Natural - This is cheap and the shrimps love it!
Hikari crab cuisine - Readily available, I usually crush this up.
Shirakura Chi Ebi baby shrimp food - Especially for babies - smells like yeast (promotes micro bacteria apparently).
Once or twice a week I replace their normal food with one of the following;
Spinach - frozen spinach for the supermarket, microwave a small amount and allow it to cool.
Occasionally they get a bit of crushed up tabimin or algae wafer.
I also have pieces of Indian Almond leaves in the tank
Spirulina algal wafers and vegetables - cucumber, courgette, carrot (cooked) and melon rind. I also like lots of biofilm for them to pick at.
If you want the shrimps to colour up you need a diet rich in "carotenoids", (accessory colour pigments derived from plants and cyanobacteria.) In fish food Astaxanthin is apparently the "wonder" chemical, they use it to make farmed Salmon fillets and captive Flamingos pink. TA aquaculture sell "Red crumb" (in the UK) which is "rich in Astaxanthin", fish like it and I assume shrimps would be keen to.
My shrimp tank is basically just ketapang leaves as substrate and moss ball with some java moss on lava rock. Tried feeing my high grade CRS with so called specialised CRS food and guessed what, they all ignored it! They rather just grazed on the ketapang leaves and the moss! Wasted Â£15 on the food. If I were you, I'll save on all those commercial food and get a whole big bag of ketapang leaves
I like leaves for shrimp as well. They seem very fond of grazing on Loquat and Oak leaves as well. One of the little tanks in the lab has lots of leaves, moss and shrimps and I only feed the RC shrimps cucumber or courgette occasionally, and they've done fine. One interesting thing was that when I "stored" a filter sponge in the tank (I wanted to get some rotifers from it for a class) it was almost instantly covered in all sizes of shrimps, all industriously picking away.