Hi,

First of all you should specify your work. Is it for biodiversity studies, or antimicrobial effects, or just isolation of culturable bacteria?

Any way

1- If you wanted to just isolate culturable bacteria it seems that these articles are useful. However, to find an appropriate method you should provide sufficient info about the condition of the coral or at least give the species name you wanted to isolate its bacteria.

A.Bacteria Associated with the Bleached and Cave Coral Oculina patagonica

http://link.springer.com/article/10.1007%2Fs00248-007-9297-z#

B. Characterization of culturable bacteria isolated from the cold-water coral Lophelia pertusa.

http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6941.2011.01115.x/abstract

2- if it is for biodiversity studies, please look at this profile (belong to Prof. Farooq azam a marine microbiologist and one of the great scientist in the field of microbial diversity). You will find so many article that might be useful.

https://www.researchgate.net/researcher/38186636_Farooq_Azam/

Also look for this web-address which has many database and articles about coral microorganisms:

http://coastal.er.usgs.gov/coral-microbes/