Chitons are little tiny creatures that crawl all over the rockwork grazing for film algae. As you can see above, sized against a dental tool while crawling on a cutting board, these critters are small. This one was on the shell of a Maxima Clam. There are many kinds and colors, but their shape tends to remain the same. I have seen larger ones occasionally. Check your tank late at night and see how many you'll find; you'll be surprised. Reef-safe.
This recognizable pattern is created by Cerith snails (not the snail you see munching to the right). The thousands of white dots left in a serpentine pattern are cerith eggs, which when left unbothered will result in cerith babies! I've seen this pattern appear in my tanks on occasion. Unfortunately they were laid right over the silicone which spoiled the photo. Reef-safe
This is a Cerith snail. These are great algae eaters and can be found in many places in the tank: on the rockwork, crossing the sand and cleaning the glass. The benefit of these guys is that they have the ability to right themselves if they fall off an object, thus they don't succumb to hermit crab attacks as easily. Rather than lying there helpless, they get right back to what they were doing before.
The subject of this picture is the tiny snail in the dead center. It is a Collonista amakusaensis, which is quite a mouthful for such a tiny guy. It is about the size of a BB, and is hiding in the shade of an Astrea above. These tend to come in as hitchhikers, and breed quite easily. If you look at your tank late at night, you'll typically see lots of them once you know what you are looking for. They never get any larger, and seem to assist in eating some algae. In the next image, with some other inverts to get a sense of scale. Reef Safe.
I bought this Target or Spotted Mandarin - Synchiropus picturatus - to help consume and remove flatworms from my 55 gallon reef. Unfortunately, this fish doesn't seem to find them the least bit appetizing. However, it has found plenty of other food to eat, including prepared foods and even pellet food. Although it is a slow moving fish, it is extremely elusive when I try to photograph it. Reef-safe.
In January '04, our club meeting at one LFS scored me this lovely fish. It is an Orange Mandarin. I'd never seen or heard of one this color, but I did have a Green Target Mandarin that might like a mate. This female was chased by the other for months, and I thought they'd never get along, but finally they cruised the 55g each day searching for food. Because of the fish I kept, I also hatched live brine shrimp every 48 hours to assure the Mandarins had live food.
Glass Anemones, or Aiptasia, are a real problem in reef tanks. They spread quietly, and retract quickly when reef keepers attempt to kill them. Using Kalk-paste, they can be injected until they melt away. However, all of the tissue mass must be removed or new aiptasia will return. Removal is best done outside of the tank. Peppermint Shrimp and Copperband Butterflyfish are natural predators, as are Berghia nudibranchs. Do your best to keep these pest anemones out of your tank.
Astrea snails are good for algae control, but you need to rescue them if they fall off the glass and land on their backs. They'll be stuck and could be eaten by fish or hermit crabs. If you don't mind righting some snails as needed, they'll work hard for you.
Copepods are found in predator free zones, and are food for mandarins and wrasses. For seven years, I'd never seen one in my tanks, no matter how many hours I spent studying the sand and rock, day and night. However, one day I noticed tiny white specks on the glass of my son's tank, and there they were! Copepods are part of the food chain, and you can purchase them online and then add them to your refugium where they can breed in safety. More than reef-safe, these are reef-desirable. They eat small planktonic-sized foods, and are part of the food chain that consumes detritus.