[Sk8r]

I'd be real surprised if a lawnmower will eat caulerpa---if they do, somebody please let me know, because they would be a real boon in that department! Only thing I know of that really gets caulerpa in a smallish tank is one mean refugium [with cheato!] and a zealous anti-phosphate campaign. They're not going to be interested in much except hair algae and film algaes.

Keep an eye on your sandsifting [goby?] A dragon goby or diamond goby [same thing] is too much sandsifter even for a 55, and is just about right for a 100g IF you don't mind him keeping the sand almost too clean for good tank health.

If [when] your sand-sifter starts looking lean in the middle, or slows down, back to the fish store for him, to save his life. About the only sandsifter that is safe in a smaller tank is one of the shrimp gobies, notably the yellow watchman: his sand pile is about 6" diameter. A dragon ranges out a foot and keeps moving from spot to spot.

I'm very fond of chromises, but they have one nasty habit [being damsels]: the strong kill off those they consider to be one chromis too many. Don't know how many people on RC have made the complaint: my chromises keep disappearing...or...I had six. Now I have 3. They're often sold as schooling fish, but they're happy as singles, too---especially as they're safest as singles. The only thing I ever saw that could scare chromises badly enough to keep them in a school and keep them from fighting was a blue velvet damsel I once had [almost as mean as the dottyback!] who regularly terrorized them from end to end of the 100g tank. [Note: schooling is not actually a 'friendship' behavior; it's a 'please eat somebody else' behavior, and usually manifests when the fish in question are terrified of being eaten by something else in the tank.]