I'd post that question in the main forum. You'll get a better range of advice than I can offer (though I will ask the standard question of "what are your ammonia/nitrite/nitrate ppm readings?")
And the tetra may have been eaten. Fish will often pick at dead fish, and small ones like tetras can die overnight.

hey , have ? I had bad fish prob , dont know what happened here , ok , i got two angels and three rummy nose tetras from a lfs sat , and when i got home the angel was dead ! and i can't find one the rummy nose tetras in the tank, i think he is dead also ! could it be my water or what ? I have looked everywhere for the little guy !

They should be fine together, as long as the pictus are in a group (they like a few of their fellows) and in a big enough tank (pictus get to around 6")

should a pictus catfish , go good with a angel fish ? just curious ?