I also need to Know how many pounds of live rock I need. (How long should I cycle it?)
See the FAQ for basic LR info:
http
/www.fishforum...e-aquarium-faq/
I was also wondering if a mantis shrimp would be too large for the tank.
Read up on the mantis species that can be found in the trade as there is a huge variety in size. Neogonodactylus species are commonly kept in tanks this size, but as a species tank, not community. You will have to either do a mantis tank or a community tank; mixing the two is very likely to result in deaths over time of the community species.
I know need a clean-up crew, but I don't know how many snails and shrimp I need.
Nobody can give you a correct number up front. Add a few snails and see how much they impact the tank and then go from there. Going too fast will result in unnecessary deaths. Also, if you want a mantis, they will eat these.
Shrimp are not really CUC animals in the standard sense because they are pretty fragile. Hermit crabs are normally employed as the first Crustaceans in. In a 20gal you could have a few peppermints but more than 2 of any other Lysmata species is a bad idea. If you put a CBS in, no skunks or bloods.
I wanted to get a few unnaggresive, inexpensive anemones.
Well, there are a some big problems with the anemone idea...
- No anemones in a new tank. 6 month maturation time minimum in any tank before considering adding an anemone. Anemones are extremely hard to care for.
- This tank is a nano and they are hard to keep stable. Anemones in a nano are pretty much a "no" for beginners, even at the 6 month mark. It's a lot better to get comfy with corals for quite a while before considering any anemones.
- Any SINGLE normal hosting species anemone can take over a nano-size tank. BTAs are the usual choice for easy hosting with clowns and they grow quickly when healthy (and other hosting species will also grow really big even if more slowly).
- You can't place an anemone like you can a coral. Anemones go where they want and you just have to let them. Even with a small anemone, if it moves, any corals in the way will get toasted or the anemone will get melted if it hits something more potent than itself. For this reason, anemones in nanos are usually a "no" even for experienced folks when the goal is to have a mixed reef.
- Rock flower and minimaxi anemones, although they stay fairly small and are more suitable to small tanks, are not a hosting species. Giving a clown access to an anemone that it wouldn't normally host in can sometimes result in the clown being burned if it has a strong desire to host. Similarly, if the anemone is too small relative to the clown, a persistent clown can easily kill a small anemone by buffeting it to death.
- Powerheads MUST be covered if you don't want to run the risk of waking up one morning to a nuked tank full of anemone soup. Covering powerheads decreases flow and adds more work (regular cleaning/replacement of the covers). You will see examples of people running tanks with anemones andunprotected powerheads, but they are still running that risk regardless of how confident they are that the anemone will stay put. All it takes is for the anemone to get upset overnight and release.
So...basically an anemone is a bad idea for this tank, particularly if the cost factor is more important than picking a hardy starting species.
Very bad idea in this size tank. They need a big group to not pick on each other, which is too much for a nano. People even have problems with chromis in tanks twice this size.
Not together in a nano! Please read up on compatibility for these fish.
