I agree on separating them for a bit. Retics are sooo sensitive to competition of any kind. The 40 should do nicely for a while, I had my two retics in a similar setup for about 6 months without any problems. Twice weekly water changes of at least 40% and massive overfiltration seemed to do the trick. Do try troutworms if you can get them, my retics ate them immediately out of the bag but I did have to chop them into tiny pieces. It might take them a while to be able to eat anything big, I noticed retics have issues with that. Once you get them on troutworms you can throw in some clam at feeding time and they should learn to accept other frozen foods as well, but dont expect it to happen in a week. Mine took just over 2 months to accept anything other than worm and I have an orbignyi that still wont eat anything else. BTW, where did you pick these guys up and where are you getting blackworms? Somewhere in MA or are they from ECZS? Best of luck with them!