Getting fish to eat new food

Lately, i've been reading up on the benefits of a varied diet for fish, and I want to provide more for them than TetraMin Pro every day. The problem is, they won't seem to eat anything else. They'll pick at Tetra ColorBits and frozen brine shrimp, but that's about it. I went on a shooping spree and got Omega One Super Color flakes and small pellets, frozen brine shrimp, and New Life Spectrum Grow and Discus foods.

I've fed all the different types at various times over the past week or two, and my fish, especially the angels, still won't touch anything but the TetraMin Pro. Here's a list of what I've fed them:

-TetraMin Pro (they love this stuff)
-Tetra ColorBits (the discus eats this up and the silver dollars seem to like it, but the angels won't eat it)
-New Life Spectrum Discus (no one eats this but the pleco after it's sat ont he bottom for a while)
-New Life Spectrum Grow (thought maybe the discus food was too big... nope, same deal)
-Omega One Super Color Flakes (The angels will at least pick at this, but then they spit it back out whole, no one else will touch it)
-Omega One Super Color Small Pellets (it's like it's not even there. they all totally ignore it)
-Nutrafin Max Spirulina Algae Flake Food (my malawi cichlids tear this up every day as their staple food and my guppies like it too, but again, no one in the 75g wants to eat it. They just spit it out)
-Hikari Discus (again, no one eats it, but i think it may be too big for them)
-Hikari Algae Wafers (really no point, as these are for the pleco, whom i have no troule feeding, although sometimes the dollars will nibble on them too)
-Frozen Spirulina-Enhanced Brine Shrimp (this gets eaten, but not as fast as most fish scarf down frozen food)

My main problem is getting my Angels to eat something other than TetraMin Pro. They've lived off the stuff since they were dime-sized and now, almost two years later, it's like they won't recognize anything else as food. Should i just kinda "starve" them until they take other food or something? Maybe give up and just keep feeding them nothing but Pro? I've tried mixing some new food in with the Pro, but they pick out the familiar stuff and leave the rest. :duh:

edit: Oh yeah, one thing the Silver Dollars will eat is chunks of jungle val from my 10g tank. When i prune the vals, i rinse off a few of the bigger chunks and put them in a veggie clip. They tear it up.

Yeah, they're healthy and active, but i just feel like they should be eating a better variety. I know I'd get tired of eating the same thing every day, even if it was good for me.

What's the difference (other than the obvious) between frozen and freeze-dried? Could i substitute freeze dried, as it's less cumbersome to store and work with? Or is the nutritional value signifigantly lower? I also saw a jar (yes, a glass jar) of daphnia in water. It was only 99 cents for the jar. I was thinking about picking it up, but knew nothing about daphnia and was a little wary of how long it would last. Anyone ever seen/used this before?

Also, I think my biggest thing is i'd like them to start eating the spirulina flakes, as a good source of vegetable matter. I've seen amazing growth out of all the fish to which i've fed the spirulina flakes, from my mbuna to guppy fry to marine damsels.