Biocube 29 Fish

[wavemaster]

Looking for fish suggestions to complete my tank. Tank has been running for 6 yrs.

Current stock:
- 2 black and white ocellaris clowns (have been in tank for 1 year and are a bit agressive but very small)
- blue/green chromis
- blood shrimp
-sand conch
-hermit crabs
-snails
-25lbs live rock
-corals (green star, kenya tree, mushrooms, big green frogspawn)

Would like a fish that is interesting and fun to watch. Don't want something that is too hard to keep and it has to be safe with current stock. The chromis stays near the top and the clowns stay in the middle, so I would like something that stays near the bottom . I really like the sandsifting diamond watchman gobys and am leaning towards that. What do you recommend?