As for colour, the squamosa hasn't changed other than going from about 3" to it's present size of close to 11".
One crocea hasn't changed at all colour wise but it never did have fancy patterns in it, just the purple with varigated markings.
The other crocea used to have gold markings but now just has the blue varigated markings on the purple mantle, the same as the first crocea.
Both croceas have grown much larger but nowhere near like the squamosa.
As for feeding, in almost 13 years, I've never fed my corals, anemones, or my clams directly. I feed the fish and whatever gets by the fish the other inhabitants are welcome to.
There are pics on my web site from a few years back, of the clams in one tank, spawning both at the same time, one squamosa the other a crocea. I thought that was weird.