| Based on your questions, I'm going to assume you bought the Mandarin on impulse because of the colors?
Do it and yourself a favor, take it back. Mandarins should not be in anything smaller than a 75 gallon with an established copepod/amphipod population, meaning the tank needs to have been up for probably at least a year, and/or have a refugium with a good pod population.
All Mandarins do is swim around and eat. I read somewhere that they eat a pod about every 8-10 seconds. Only a few people I've found online have trained the Mandarin to eat frozen food, and that took several months of work. Your Mandarin is probably starving. It is best for you to take the fish back ASAP and do more homework on your fish selection.
Sorry to come off harsh but I wanted to give you the truth. |