CUC FOR A 20 GAL REEF TANK

[L0L_Z]

So basically I’m researching for a 20 gal reef. I’m DIYing an AIO and plan on using an aqua one powerhead for return and flow. Will have about 5 Kg of lr and 15 pounds of sand. Will have mostly lps and maybe a single montipora. lps like Trachys, lobos, hammers torches, sun corals, and acans as well as softies like zoas and mushrooms

Fish stocking (planned)
a clown
yellow head jawfish
royal gramma
falco hawk

So questions
What CUC? I want an urchin and a cleaner shrimp but anything else? Snails?
Can I put a kind of colourful goby/blenny instead of the clown? I’m hoping for a diamond goby as there’s one at an lfs that eats frozen and pellet and I have seen it eat on multiple occasions.

 

[blaxsun]

A small orange conch (or similar) for the sand, a several cerith snails, nassarius snails, 2-3 trochus snails and 3-4 ring cowries.

 

[L0L_Z]

What about a fighting conch instead? I’m pretty sure I’m gonna be getting those snails and cowries.