For a rubble pile you can break up a base rock with a hammer, or even go to a garden store and ask for some lime stone rocks. They come in large bags for rock gardens planting borders and such. They are grey to white in color. Even marble rocks are easy to get and they are also white. They ewill cover with algae and coraline like everything else. Pods were likely still be in your tank if you had much algae. At least if there are any hiding places you probably will still have some. As long as they can feed they will multiply to fill the homes provided, meaning if they have places they will not be eatten they will populate those places fully if food is available. Phytoplankton can be purchased to feed plankton and filter feeders. Bottled and frozen phyto is reasonably priced. Try what you can afford to try if you really want to keep a mandarin, most peoples mandarins die before they ever start eatting dead food. If you can keep them a live long enough to get used to captivity with live pods, live rotifers, and live shrimp naupuli, then you have a good chance of their starting to eat frozen foods. Large LFS's in the states ought to have live rotifers and live naupuli are simple to harvest and there eggs are available at all pet strores, even Walmart. Do not try starving a mandarin into eatting dead foods as it will likely choose starvation. I find Mels ways often tacky but usually effective, but I normally have no other fish in my coral tanks and still can many mandarins to eat dead food. Perhaps the fact that they usually have plentiful live food is just reason not to eat dead food. Before I started feeding my SPS I could never keep a mandarin long term as they did not have plentiful live foods, and would not take dead food and they had no other fish in the tank then either. Usually my mandarins only stay in my tanks now for 6 months or so before going to a customers tanks. I definitly need to hang on to one and see how long it will live. I know several customers are at least two years old. They feed (now fresh, but for most of that time bottled) phytoplankton and rotifers to their corals.
