Hi David, Viper (and others)..... Are you sure that is cyano bacteria (red slime = cyano, right?)??
One the photo the rocks looks like it has a strange, but brilliant covering of corralline algae....
The most common solutions for marine ich:
- fresh water dip (get the fresh water up to the same temperature/pH as the tank, the catch the one fish, place it in the fresh water for up to 10 minutes (depends on how the fish "handles" the fresh water, if it looks like it's becoming worse off, then catch it again and place it back in the tank - repeat this for each fish you have that has marine ich)
- alternatively: make use of a quarantine/hospital tank (same water type/chemical composition/pH/temperature as the main display tank - use some medication for "Marine ich" in the water, catch the applicable fish that has marine ich, place them in this "hospital tank" for up to 3 weeks (until the marine ich has dissappeared) - while doing water changes, often)....
- thirdly: try making the tank's water slightly hypo-saline (meaning: lower the SG of the water) - I believe that the ich then also dies off??
Viper: I have read somewhere that marine ich does not get hold of one's fish so quickly, with a very high water flow in the tank, as the ich babies that's free-swimming, gets into the filter too quick.... if the water flow is too little, then this happens easily (especially when the fish are sleeping)....
This is my little bit of input - perhaps someone has some better ideas than me....
Cheers!