Corals
Choosing corals for your nano tank can be fun and challenging. With such a small volume of water, I would recommend selecting hardy corals and preferably those that have been aquacultured in aquariums. There are now a whole host of corals that are easy cultured by companies, shops and hobbyists. These tend to be well adapted to aquarium life.
If you are new to reefing (as recommended earlier), it is a good idea to make a wish list of potential corals you want to keep in your reef tank, post up your tank spec and wish list on UR so experienced members can advise you on suitability.
With a small tank, I would advise sticking with corals that tend to stay small or grow slowly so you can prune them. In general, I would say stick to mostly soft corals so that you don't have to worry too much about calcium, alkalinity and magnesium additions.
I have chosen to stock my nano mostly with Ricordea sp. mushroom corals. These soft corals come in a wide variety of colours, each ear stays relatively small and they are regularly aquacultured for the aquarium trade. In addition to the Ricordea I will also add a couple SPS and LPS frags I have from another tank. I would generally advise new reefers to avoid SPS and most LPS corals in a nano tank but there is no harm trying if someone local can provide you with a frag or two.
Other corals that I feel are suitable are:
Most mushroom corals: Rhodactis sp. Ricordea sp. etc
Xenia type corals
Star polyps
small leather and finger corals however, these will quickly out grow your tank so will require regular pruning
Some photosynthetic nepthya corals
Some photosynthetic gorgonians (regular fragging will be required)
Zoanthids
Possible SPS & LPS for more advance reefers
Aquacultured SPS frags
Candy cane coral (Caulastrea sp.)
Sun coral (Tubastrea sp.)- providing you can keep on top of nutrient levels
SPS & LPS should not really be tempted in a nano tank unless you have a good understanding of maintaining stable water parameters.
When it comes to fish stocking its easy over stock in a small tank. In my nano tank I stocked one damsel fish. These tend to be hardy fish but do have a reputation for being bullies. When stocking a nano with fish err on the side of caution. It is better to understock and over stock! Overstock can cause you problems with nutrients which lead to algae issues and in some cases it will harm your tank and livestock.
I would stock no more than about 2-3 large nano fish in a 35l nano. When I say large, i mean in terms of nano fish. A damsel or clownfish, which most would consider small fish when talking about normal sized reef tanks, is considered large for a nano tank! Even most dwarf angels are too large for most nanos. Please do not even consider any tangs, butterfly fish or anything that grows over 3".
Here are some fish that I recommend:
Neon gobies (Elacatinus oceanops)
clown gobies (Gobiodon sp.)
Trimma gobies (Trimma sp.)
Eviota gobies (Eviota sp.)
Firefish (Nemateleotris sp.)
Ocellaris Clownfish (Amphiprion ocellaris)
Percula Clownfish (Amphiprion percula)
Skunk clownfish
most small damsels (Chrysiptera sp.)
Small blennies (Ecsenius sp.)
Critters
Grazers and critters are important to help keep algae at bay. However, it is important not to overstock with grazers in a small tank or they will starve to death. In my nano I have stocked with 1 true mexican turbo snail, 1 red leg hermit crab, 5 Nassarius Vibex snails, 2 cerith snails.
It is good to have a range of grazers in any tank as they all tend to prefer different foods. Have some that graze off the rocks and will take more filamentous algae as well as algae films and diatoms (turbo and Astrea snails), have some that will help turn your sand bed (cerith and N. vibex snails), and have some that will feed on left over food (N. Vibex) etc.
Maturing your Nano
Over the first few weeks/months of setting up any tank you must allow it to mature. It will go through phases where the bacteria develop and the tank will need to find its own equilibrium. Stocking slowly, especially with fish, will help these maturity phases pass quicker. Don't be alarmed when you start seeing diatoms or cyano appearing. These are signs that the tank is maturing and should be embraced!
photos: A mix of diatoms and a cyanobacteria developing on the sand bed
During this maturing period it is important that you keep on top of your parameters. Regular testing is essential and regular weekly water changes is recommended. This should continue well after your tank has matured
After a few months of careful slow stocking and allowing the tank to mature, it was more or less complete. Well, as complete as a living breathing tank could be! Of course with any tank, it must be regularly maintained, but I had at least reach a point where I could really sit back and enjoy the tank.