here is a little something on the care of the mandarin.
http://www.wetwebmedia.com/mandarins.htm
a couple of abstracts from that.
Foods/Feeding/Nutrition:
Whatever other writers have stated, Mandarins almost never accept enough of anything other than live foods that are omnipresent in their system to sustain themselves. A nutrient rich live rock reef tank, read that as one heavily populated with hard substrates, with substantial interstitial crustacean and worm, and other small sessile invertebrate life of about 100 gallons will support one individual. And this assumes you have no similar food-competing tankmates.
In the wild their food choices are principally small crustaceans and worms. You can culture these "incidentally" in a large main/display system with lots of substrate and/or live rock, but adding a live fishless refugium will go an immense distance in assuring your mandarin/s receive sufficient live food. These fishes cannot live on dried-prepared or frozen/defrosted, or chopped meaty foods.
Foods/Feeding:
As stated over and over, feeding, or rather a lack therein is THE common cause of loss of these animals. They spend many hours seeking out small live invertebrates living in/on live rock and substrates. If these are not present or otherwise supplied, you will see your mandarins sides sink in and its vigor wane. Live foods can be bought on a regular basis, cultured in separate vessels, in an attached fishless refugium. Starter cultures for these organisms can be purchased from companies that you can find on the Internet using the search terms: "live plankton fish food".
Do not fall into the trap of offering nothing but adult live brine shrimp, suffused with supplements (e.g. Selcon) or not. Itââ"šÂ¬Ã¢"žÂ¢s not unheard of that a dragonet will accept (with training) frozen/defrosted foods in place of live, but it is rare that non-live foods sustain them.
so in your tank all your shrimp not just the pistol are competing with the madarin's main food source. and the damsel i am sure is getting some of those pods too. perhaps the population is depleated so much you dont see him hunting the rocks much, nothing left. the ich yeah try to treat it and continue with the medication for up to 30 days after you no longer see any sign of ich. ich can live undetected so you must keep the medication going well after it appears to have gone. if posible take out everything in the tank to treat, dont want the rock to soak up and become saturated with any medication.
yeah get more pods you need them. i hope the link i gave helps.
a key to keeping caluerpa from crashing (or going sexual) is just keeping the light on it 24/7 or alternating the lighting so when the main tank light is off the sump light is on. i perfer the 24/7 lighting, used it for years with no problem ever. but cheato is good too, just need more light and flow. and the addition of iron and iodine will add in any macro algea growth.
if the madarin makes it to the 210g and you let the pod population build up a bit he should be cool, but do try to set up the 210g ASAP. as long as he is hunting for food on the rocks you still have a chance with him. o one last thing make sure there are no fish or crabs or shrimp or anything in the sump that will munch down your pods.
