Bird's Nest Coral, Caliendrum becomes white   6/17/06 Hello, first of all I want You to Know I am Italian so my English is quite (not to say very) poor. excuse me for next errors. Thanks. <I wish all "native" English speakers were as literate and gracious. Thank you> As write in the title in my tank there is a little fragment of Seriatopora caliendrum (dimension like an apricot to give an idea) that is becoming with from the center to the tips, even if it continues its tips growth. Tips are brown (the very top are white because of the growth) becoming brighter and brighter to the centre of the branches until the white of the skeleton is visible. Tissue seems to be in place (even if you can see through) and so the polyps do but all zooxanthellae had gone. <Yes... this appearance is typical of wild, healthy specimens...> Tank set up: 85 litres full of rock coming from my old big tank, 1/2 inc aragonite sugar  from old tank, 150W HQI 10000K, 4000 litres per hour global movement and Tunze 3110 skimmer. Temp regulate by heater and fan with digital controller 27-28 Celsius. Refill with CaOH. water change weekly 10%. I have an upstream refugium of about 40 litre. DSB, Chaetomorpha growing quite fast and Xenia inside. Light if it's interesting 2x24W 3100K + 1X24W Blue. No fish in tank, only 2 Lysmata amboinensis 2 hermit crab, many snails. Only a Synchiropus ocellatus in refugium (I take it to save it from another horror tank) long a little more than 1 inc. What do You think about this disease ? Have You ever eared about something like that ? Thank You for your answer. Marco Nanni Italy <I don't think you have a problem here Marco. Take a look on the Net re this species appearance in the wild. What you describe is a healthy colony. Mine here: http://www.wetwebmedia.com/pocilloporidae.htm If anything, I might increase your weekly dosage of Iodine/Lugol's with your water changes. Bob Fenner>