I've had my 29G frag tank up now for a few months, it replaced my earlier 20G long tank. I've been slowly adding rock and such to it, and it has no fish or crabs, just a couple snails. The interesting part is watching the population of pods, worms, and other little critters that I'm seeing. Since there is no predation I find that the pods, mainly gammarid amphipods are out all the time, and I'm seeing quite a few small worms of different varieties out and about as well. At night if I put a flashlight up to the tank, I can sometimes get a pretty good swarm of fast swimming critters congregating at the light. Not sure what they all are, but they zip around quite a bit and are really fun to watch. A little hard to take pictures, just a bit too dark to get anything that can be recognized. I recently found a stomatella varia snail cruising around, and I'm hoping to find a few other things over time. It's been so long since I've had any new live rock, it's fun just to watch what comes out of it.

Its always nice when you can see something new.

This tank is really fun, and is beginning to show me how much diversity you can get when there are no larger predators in the tank. This tank has no fish, just rock and some frags that I'm growing out, including those from the March OMAS meeting. Another key is that there are no hermit crabs in this tank, I am trying this out the advice of Ron Shimek that said they are little "eco terrorist" and will eat basically whatever they can find, not only algae.

Last night I hit the tank with a flashlight in a corner half an hour after the lights had gone out. Gave it a minute or two and the water was just swarming with little critters swimming around the light. There were larger red swimmers, almost looked like swimming worms about 5mm to 8 mm long, and then a cloud of smaller pods, including some I could barely see. And the tank is covered in Gammarids which stay out all the time, as well as fan worms of a couple different varieties.