By Nathan Peel – 2018 Writers contest award recipient!
The Mandarin dragonet (also known as the mandarin goby), is the arguably the most beautiful saltwater fish, which catches the eye of both experienced and beginner hobbyist. If you have done any research on these fish you would find that most people would agree they are not for beginners. This is for several reasons, but the main reason is the fish’s dietary needs. Although dragonets are more difficult than other fish, it is possible for beginners to keep them successfully in their saltwater aquariums.
The Mandarin Dragonet Diet
A perfect beginner fish is a hardy, disease-resistant, and inexpensive fish. The Mandarin dragonet is all these things. They are not sensitive to slight fluctuations in water parameters, they have a thick slime coat which makes them disease-resistant, and they can be bought for 20-30 dollars. So what makes dragonets difficult? It is the diet. Dragonets are categorized as finicky fish. They eat small crustaceans such as copepods and amphipods. This is what they naturally eat, but it is common to see hobbyist feeding their dragonets frozen food. While it is ideal to have a dragonet that eats frozen mysis or brine shrimp, it is also important that the fish has a stable supply of copepods in their environment. This is because of their fast metabolism, which is similar to a hummingbird. Their metabolism requires them to eat small portions all day and not two large portions twice. This is why it is best to have copepods in your tank even if your dragonet is eating frozen food.
One of the most frequent questions asked by beginner hobbyists is “What tank size do in need for this fish?” Most people assume it is based on how large the fish grows to be. While for most fish this is this the case, for Mandarin dragonets it has to do with their diet. A Mandarin dragonet could easily live in a 20-gallon tank and have plenty of room, but it is not the actual fish you need room for. Copepods live in rocks and in the sand bed; the more sand bed and rocks you have the more copepods can live in your tank. A Mandarin dragonet can easily wipe out a whole population of copepods in a 20-gallon tank in a short amount of time. The reason you can not just feed more is that it will have a negative affect related to having too many nutrients. So unless you have a well-filtered tank, you do plenty of water changes, or dose pods often, Mandarin dragonets should only be in tanks 45 gallons or larger.
Mandarin dragonets come from large coral reefs in the wild. They are reef safe and will be happier in a reef with a large biodiversity. It is common for tanks in their early stages to have low biodiversity because it is unmatured. This is why dragonets are recommended for more mature tanks and not newer tanks. Tanks with large biodiversity will have a natural supply of copepods that live of the natural phytoplankton in the water. If you have a newer tank and you want to keep a dragonet, you need to dose pods and phytoplankton every couple of months. Not only is this good for your dragonet, but it is also good for your corals, other fish, and the overall well being of your saltwater aquarium.
Like I said early, copepods live in the sand and rock in your tank. It is important to have plenty of rocks and a sandbed. It is not recommended to put dragonets in a bare bottoms tank because of this. It is also good to have a refugium built into your filtration system. Here copepods can reproduce and live without being eaten and then eventually go into the main tank. This will allow for the supply of copepods to be even more stable for your fish.
Copepods: A Mandarin Dragonet’s Favorite Food!
So you know dragonets need copepods to be healthy and live successfully in your saltwater aquarium. But how do you keep copepods in your saltwater aquarium?
It is best to add copepods after cycling or in the late stage of cycling your tank. Copepods can be added after your ammonia and nitrites fall to zero and your nitrates are decreasing. When you add them, you should not have any fish in the tank for at least three weeks for the best results. This will give the copepods time to settle in, reproduce, and take over your tank. It is good to also dose phytoplankton at this time to provide food for the copepods
When adding your copepods, you could simply just dump the bag or bottle into your tank, but this method would not be as effective as the way I am about to tell you. I recommend you turn all your pumps and powerheads off for 24 hours. If you are adding phytoplankton or pods to your sump, this includes your protein skimmer. Then take a turkey baster and use it to spray the pods into holes in the rocks and onto the sand bed. Do the same with your refugium; use the turkey baster to spray the copepods directly into the refugium area and the media in it. Your overall goal is to try to get as many of the pods into the rocks and not get filtered out.
Following both these methods will increase the survival rate of the pods and the chance of sustaining a healthy population of copepods for your Mandarin dragonet.
Mandarin dragonets are beautiful saltwater fish that require a food source all day long. The most natural and efficient way to meet these needs is by adding copepods to your tank. Copepods need lots of rocks, a sand bed, and possibly a refugium to provide a long-lasting food source for a Mandarin dragonet. When followed, these recommendations can allow even a beginner to keep a healthy dragonet successfully. Knowledge and research is the key to being successful in this hobby and there is no way of escaping that.