Through the Microscope with Chris Wohl (AI Staffer)

What EVER is that Dragonet up to?

(and talking about nomenclature)

            Scooter ‘Blennies’... Mandarin ‘Gobies’... commonly occurring names in our hobby. These scooters and mandarin’s belong to a family of fish called Dragonets. They are neither Goby (Family Gobiidae) nor Blenny (Suborder Blennioidae) , and belong to the family Callionymidae. Though they should  be referred to as Scooter and/or Mandarin Dragonets, we often use the ‘common’ names to describe them. It is however important to recognize them as part of a different taxon because of their different diets and lifestyles.

            So during the day, Captain Dragonet is motoring around the tank, apparently ‘pecking’ or ‘kissing’ the rocks and surfaces in the tank. What on earth is he doing? Many of the dragonets we keep in the hobby (such as the blue/green mandarin, or the Red Scooter ‘blenny’) are carnivorous ‘pod’ consumers. Typically they are eating little critters called ‘Copepods’, one of the largest biomass (and yet smallest in physical size) of animals in the world!  Most of the critters your fish are eating are adult copepods of many different types... their sizes ranging from 0.1mm in length to 2mm. This is what your fish is normally eating when it appears they are not really catching anything. These critters are often visible to the trained or attentive eye, and will be much easier to spot in   an un-frequented region of the aquarium or in something like a refugium. Keeping a healthy (and plentiful) population of pods alive in your aquarium is important for your fish. Refugiums (without fish, and with lots of plants) with low flow rates will help ‘farm’ pods for your fishy, and since it can be a significant part of their diet, dosing phytoplankton into the aquarium will also ‘feed’ these critters (while benefiting your corals and other filter feeders as well). Curious one day about what was in my tank, I took a few pod samples to the biology lab and inspected them under the microscope. Here are some pictures of them, up close & personal:

            Has your dragonet been disappearing? Often (usually) at night, and occasionally during the day, these fish bury themselves in the substrate - a way to protect their delicate selves while they sleep or their bodies heal. Do not be alarmed. Some species of dragonet are even sand dwellers and almost ‘sifters’. For these reasons, it is important that if considering purchase of a dragonet, you have a fine or soft sand in your aquarium.

            We hope you learned from and enjoyed this post! Now below is an idea about some of the little friends (whom are both harmless and beneficial) that you can find in your aquarium!