I've had these torch corals for about 4 to 9 months and they have been doing great until recently. Today I have noticed the gold bar torch coral (1st pic) is losing colour on some of its tentacles. Also, on all torch corals the length of the tentacles have decreased and have shrunk a little where the white base has increased in size and the actual tentacles have decreased (refer to both pics). They are in an area of moderate flow and receiving sufficient light. Parameters are:
Ammonia, Nitrite & Nitrate 0
Phosphate ranges from 0.5 - 1.0
I dose Red Sea ABC+ reef foundation every 3 days as well as ABCD coral colours. I also dose 10ml of Red Sea NO3PO4x when ABC reef supplements are added. They also get spot fed frozen brine shrimp once a week.
Can anyone suggest why the discolouring as well as the decrease in size and thickness of the tentacles are happening?