OK well here goes my input
The mention of a powder blue worries me. These fish are very delicate and if the tank is too small (which this is) then it will get whitespot continuosly or even die from stress. They are also extremly aggressive so even if you were successful you would still have aggression problems with this fish as its territory in the wild is far larger than your tank.
Yellow tang.. ok I will say its possible to get this fish in but the tank is still unsuitable and the fish will be stressed as it grows. You must remember that 99% of tangs are highly territorial and will defend their tanks from anything they percieve asa threat. Small tank increase this stress and they will be very dominating.
A much better tang for a tank of your size is the Yellow eye Tang.... pictures dont do them justice as these fish are beatiful to watch. They are also excellant aglae removers.
Damsels...
Im afraid to say that i have yet to see a damsel that is friendly.. they have only various degrees of evil
If you want damsels then i alway suggest you keep 4 or 5 of these fish as they WILL fight and its better to have other fish that can fight with them.. having a community of damsels usually means they will bicker amongst themselves and leave other fish alone. of course this is risky cos if they all get along well then the other fish have 4 or 5 damsels in the tankto contend with
Chromis are an excellant fish.. if you want another nice colourful shoaler then how about Anthias? they are a little more delicate than the chromis but they have lovely bright vibrant colours.
As for the clowns...
I would not mix the species but i see no reason why you cannot have 3 or 4 of the same species in the tank. I have seen tanks with 4 clowns in there. One will become dominant and the rest usually remain as males and non-fertile males. If you choose this route then i recomend the perc clowns as they are the least aggressive when compared to tomatoes or maroons etc.
Anenomes? DONT
here are a few reasons.
Anenomes need perfect water conditions. This is something that people new to the hobby find difficult to keep stable enough and thus keep the anenome happy.
Lighting for anenome needs the best.. Halides are very important for anenomes as their primary source of energy is sunlight
If an anenome moves around the tank it means they are in search of better light or better water. this means all they come into contact with will get stung. Corals that cannot move out of its way are going to get severly damaged if an anenome passes by.
There is no gaurnetee that an anenome will accept or be accepted by clowns. Clowns can be very very choosy and they might not even accept the anenome.. unfortunately there is little to nothing you can do about this
Sadly, the sheer number of anenomes in the wild means they are being taken from the ocean to make money.. lots of money.. what many people dont know is that they have an extremly poor survival rate. about 1 anenome out of every 100 collected will survive long enough to reach the wholesalers. and probably 1 out of every 100 sold in your lfs will make it past the first 6 months in a persons tank. As you can see, this is an appawling survival rate and considering that these creatures can live for 100s.. even 1000s of years in the wild then we cannot truthfully say to anyone that we can keep anenomes sucesfully in tanks.
If you insist on an anemone then i urge you to give it the best chance for survival by learning more about the hobby first. allow the tank to fully mature, this takes about 12 months. During this time i would ask that you learn as much about their keeping as possible.
If you merely want the clowns to host something then i recomend the Sarcohyton leather mushroom. Its far less demanding on all aspects and is an easy beginner coral. Lighting doesnt have to be halides and they will live under far lower light conditions. water quality doesnt need perfection as these coral survie much better in higher nutrient water. These corals dont move around and lastly they dont sting and eat other fish/corals.
Just so you can see for yourself how easily a leather mushroom can be an effective host, here is a piccy of my old clowns thriving in the sarcophyton.
and my maroon in the same coral (when the coral was in a different tank)
Hope this helps
