I haven't fed shrimp in a while, but when I would go buy some there would always be some already peeled ones in the market. Do do you buy it from a fish market or from the freezer section at the store?
I only feed without the shell. Since I cut the shrimp into pieces, I'd have bits of shell flying around and I have 2 rays, and 5 14-16" peacok bass, the last thing I need is one more thing that'll fowl the water.
When I feed unpeeled prawns my polys get them with the shell . I also feed peeled shrimps and there is no difference in behaviour of the polypterus. They eat both ways with big enthusiasm - only the tails need longer to be eaten. I've heard, that the quinine of the shell is healthy for the polypterus because in nature they also eat insects like bugs and so. Maybe the crunchy shells are like chips for them...
And if the polypterus don`t eat everything, the catfishes will eat it.
I wouldn't feed the shell. Just too much risk with it possibly going down the wrong way and cutting their organs. Another thing to remember is that shrimp isn't too healthy for bichirs because it's thiaminase
Is thiaminase also a problem when the shrimp is boiled? I know that some fishes are not good to be fed 'cause of thiaminase - but it´s new for me, that shrimps also are difficult. Isn't this a problem that can easily be solved with adequate nutrition?