If you’ve read about my fish tanks, then you may know that at one point I had a 5.5 gallon reef tank which was home to a Mandarin Dragonet. Ok, so mandarins have long been thought of as a very difficult fish to keep, and I would say that is partially true. Mandarins, when healthy, are actually very hardy fish. The biggest threat to a mandarin in a home aquarium is starvation. In the wild their diet is made up of copepods and other tiny crustaceans. Many people think a mandarin will starve to death in a tank that doesn’t have 100+ lbs of live rock. While this may be true if they are only eating pods, I supplemented my mandarins diet. Many people also think a mandarin will wipe out a copepod population in a small tank very quickly, but I can tell you first hand that’s not always true. I had Bruce, my mandarin, in the 5.5 gallon reef from August 2013 until he was moved to my 20 gallon reef in July 2016. During that time he was very healthy and there were tons of pods in his tank.
He never ate every pod in the tank, or even close to it. There were pods all over the built-in refugium, and even on the glass in the main tank. Now for the real shocker, as if keeping a mandarin in a 5.5 gallon tank wasn’t enough, I fed my mandarin adult live brine shrimp almost exclusively for a year! I know you have probably heard that adult brine shrimp has no nutritional value, but the problem is all of those facts are analyzing the content on frozen brine shrimp. Adult live brine shrimp really aren’t that terrible of a thing to feed fish, if you are feeding the brine shrimp properly.
Way before I kept fish, I was keeping reptiles and amphibians, which eat live crickets. People who keep those animals are familiar with gut loading the crickets, which essentially means feeding the crickets healthy food, making them healthier for the reptiles and amphibians to eat. The same concept can be used on brine shrimp. In the holding container of brine shrimp I fed them spirulina powder. Then about 2 hours or so before I would feed the brine shrimp to Bruce, I would put them in a cup with saltwater and Selcon in it. Selcon is a vitamin supplement many people soak their frozen food in. While soaking frozen food in Selcon is beneficial, much of the Selcon isn’t absorbed by the frozen food and is wasted. With live brine shrimp, they eat the Selcon making them highly nutritional, likely more nutritious than frozen food.
The next problem people run into when feeding mandarins is they starve because they can’t compete against other fish for food. Mandarins examine their food before eating it, and take a while to do this. While the mandarin is examining a piece of food, the other fish are busy eating everything else before the mandarin has a chance. In my small tank, I originally only kept my mandarin and a fire shrimp, the fire fish wasn’t added until recently. I would turn the pumps off during feeding time, and let the mandarin take his time to eat. He actually got so used to being fed by me, he would take the brine shrimp right out of the eye dropper. This allowed me to sneak other foods into the eye dropper and get him to eat them. This was handy if the fish store didn’t get a shipment of live brine in. After about 30-60 minutes I would turn the pumps back on.
Fast forward a year, and my mandarin actually started eating pellet food. Once he started eating pellets, I stopped feeding him live brine since pellets are nutritious and easier. Even though I have successfully kept a mandarin in a 5.5 gallon tank, I absolutely am not recommending everyone do this. It took real dedication with feeding him, that most people won’t be able to do. I was lucky to have my tank at work, because if I was out for a day or on vacation, I could have co-workers feed him for me. So I want to make that clear, unless you can guarantee to be dedicated to caring for this fish, I don’t recommend putting one in a nano tank. Also, the built in refugium definitely helped provide a sanctuary for pods to grow and reproduce, and I’m sure this helped with my success with my mandarin.