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.
I am gonna dose pods do pretty frequent water changes and I will have a large refugium or hang on back filter