Hey Richard,

It is definitely doable, I have attached a citation and link below where the researchers tagged six. The trick is tailoring your individual fluorescent tags to your specific species. Do you know who you are looking to tag? If not I would get there 16S before buying tags, then check out:

https://www.arb-silva.de/fish-probes/

and

http://probebase.csb.univie.ac.at

Hope it helps,

Cheers,

Ceth

Thurnheer, T., Gmür, R. and Guggenheim, B., 2004. Multiplex FISH analysis of a six-species bacterial biofilm. Journal of microbiological methods, 56(1), pp.37-47.

Article Multiplex FISH analysis of a six-species bacterial biofilm

Best Luck.

Chapter 3D-Fluorescence In Situ Hybridization of Intact, Anaerobic Biofilm

https://www.e3s-conferences.org/articles/e3sconf/pdf/2017/05/e3sconf_eko2017_00098.pdf

Article Fluorescence “In Situ” Hybridization for the Detection of Bi...