This tiny snail was discovered in the overflow box of my 280g reef tank. It is called a Peppermint Snail. Its shell looks glossy, and it is a relatively mobile creature. When I saw it, I dashed off to get my camera and had some trouble locating it again in an area that is only 12" x 6". It is probably 3/8" long and 1/8" wide, and projects a snout that is tough to see in this image. Reef-safe.
Nerite snails are smaller snails, yet useful as part of the clean up crew in your tank. While not visible in this image, the snail itself has a blue-hue to it, which I've observed late at night via flash light. You can special-order these creatures from your LFS if you like. They are a nice alternative and fit in areas that Astreas may not. Reef-safe
Nassarius Vibex snails are vital for DSB tanks, as they consume detritus on the DSB. Excess food, fish excretions, rotting plants are all consumed, within reason. They stir the sand with their large 'foot', and travel very fast when they sense food in the water! I've also observed them on the glass and rockwork as well as in macroalgae stalks, so they pretty much cover your tank well. Excellent part of your clean-up crew.
Tiny pods scurring about our tank are sometimes problematic, but not these guys. These are Mysid shrimp, which are very small and rather translucent. For a comparison, please note the size of the grains of sand in this image. Wrasses, mandarins and more would be happy to snack upon these little morsels of food. These appeared recently in my tank and may exist in my refugium, and this is the best picture I can get. Reef-safe.
The only predator that you have to be concerned about for plating Montipora sp. are Montipora eating Nudibranchs. They are very very small, and typically white. You may see what appears to be microscopic grains of white rice piled up in a spot, and these are probably nudibranchs if they don't blow off like grains of sand. The nudibranchs lay their eggs on the underside of the coral, and as soon as they hatch they'll feed on the live tissue of the colony. I had an outbreak in my propagation tank that grew out of control in no time.
The workhorse of algae grazers, the Mexican Turbo Snail can be quite the bulldozer as it works its way through corals and rockwork to devour nuisance algae. They are good workers, but can knock things over as they move to the next spot. Be prepared to pick up frags daily, or putty them securely into the aquascaping to keep them in place. These snails are about the size of a golf ball.
Known to eat Cotton Candy algae as well.
Keyhole Limpets move about the reef, substrate and even glass. Their body is protected by a cone-like shell that has a small hole at the apex or top. When extended, some display a delicate lace-like fringe or skirt. I have had a few of these over the years, and usually they are about .75" to 1.5" in size. Many babies about 1/8" appear in the sump, refugium and plumbing. Reef-safe.
"Pods are good" or "your tank needs pods." So what are they? They are tiny little bugs running around on your rockwork, on the glass and in micro / macro algae. Usually people see amphipods in their system, which are small and look a little like tiny shrimp. Even smaller are the above, which resemble opaque ants. This Isopod may be food to many fish, including wrasses. Usually these tiny guys hitchhike in on LR or corals, and in a predator-free zone they are quite interesting to observe. Reef-safe.
This Fleshy Limpet came in as a hitchhiker with some corals, and was simply stunning. It is very similar to the Keyhole Limpet, except for the soft meaty skirt that was extended as seen above. It only lived a few days in my frag tank, and I don't know why it died to be honest. Maybe it couldn't handle the intense lighting or the temperature of the water, but it really was a beautiful creature.
The Fighting Conch is an excellent sand sifter for DSB tanks. It doesn't grow as fast as the Queen Conch, but each one needs two square feet of sandy surface area to get enough to eat. On occasion it will bury itself completely in the sand to where one eye stalk is all you can see, and may not resurface for weeks. This is normal, and perhaps that is its growing period. They jump quite high with a very powerful foot. The snout extends across sand and glass, but never on the rockwork.