Looking for suggestions on 75 gal Tang aquarium

Hi everyone, I have a 75 Gal with 8 Synodontis lucipinnis. There is a GCCA swap coming up in a couple weeks and I would like to add some stock to this tank. I have always wanted to keep Altolamprologus compressiceps or calvus and was thinking of adding a group to this aquarium but I'm not sure if they are compatible with the cats. I'm open to any Tang suggestion really, but I do prefer to purchase fish from swap meet. Always healthy, good pricing, and fun to go to. thanks

Well, I changed the rocks in my 75. Let me know which rockscape you guys like better. The cichlid swap is this weekend, I'm still wondering if anyone knows if 4-6 calvus or comps would be ok with the 8 synodontis lucipinnis. Let me know if you have any exp with this combo. I have read that the calvus/comps can be kinda fussy.

Thanks for the comments guys. In the first set up I never saw the cats, they had so many caves to hide in. With the new set up, they do seem to swim around more. There is really just one cave that they all crowd into. The cichlid swap is tomorrow, can't wait to see what I come home with...

My son and I arrived at the cichlid swap just after it opened, a little after 10 AM. It was very busy and crowded. I purchased a pound each of frozen Mysis shrimp and bloodworms. Next I found a dry goods vender and purchased a 1/2 lb. of flake food. I bought some packages of larger snail shells for a future African shell dweller aquarium. All the while I was checking the tables for Altolamprologus compressiceps or calvus. We did several laps around all the tables and either I missed them or nobody had any at the swap. There were lots of plecos, angelfish, discus, peacocks, mbuna, and even some livebearers. I did end up buying 6 orange shrimp for my son. I guess they are a color morph of the cherry shrimp. So we came home and moved his male fancy guppies from the 10 gallon in his room to the 40 gallon downstairs. (where all the females and babies are). We then put the shrimp in his 10 gallon with his mystery snails. He is quite happy with the shrimp and I have to say they are pretty entertaining. My son now wants to start breeding the shrimp.