Depends on what type of fish you're keeping in an "agressive tank". Some fish eat snails, hermits, etc. while others will eat crabs, shrimp, etc.
In my tank, I keep 2 baseball sized Red Starry Hermits, 2 Bahama Stars and 4 Turbo Snails.
Zebra Eels will eat crabs, shrimp and sometimes small fish.
Dog Faced Puffers will eat crabs, hermits, sometimes snails and shrimp.
Pather Groupers will eat shrimp and small fish.
Choc. Chip Stars might be alright, but your Puffer may take bites every once in a while.
You could probably get away with Turbo Snails and larger hermits.
Margaritas and astreas may get munched by the Dog Faced.
And, I'd stay away from CC...definately not something I recommend for a tank but some people have luck with it. IMO, it's just a nitrate factory and needs to constantly be cleaned.
harah large hermits will be fine thank god now the hard part is where can i get them and they will be fine with any other fish i choose to put in i think if they can survive puffers they can survive anything am i right
Throw a dragon wrasse in there he'll sift the sand and make it good as new there real fun to watch as well my tanks sand was disgusting till I threw the dragon wrasse in there its really neat when the lights go off and they disappear in the sand till the next day