What do Mandarin Fish Eat?

So, what do mandarin fish eat?  And what exactly make them so tricky to keep, especially for beginners?  

These stunning bottom-dwellers live in coral reefs where there is plenty of live rock and therefore plenty of food for them to eat.  Unfortunately it’s not that easy to keep them well fed in an artificial environment BUT it is possible.  There are a few basic requirements but they are mandatory which I’ll discuss further on in this article. 

Copepods

Copepods are a Mandarin dragonets main source of food in a saltwater aquarium.  And keeping an ongoing supply of them is what makes it so tricky to keep these stunning fish.  If there are not enough copepod then your Mandarin will slowly start to starve to death.   

Although copepods can naturally be found in a tank started with live rock or live sand, they may need to be introduced if you have set your tank up using dry rock.  There should also be enough live rock and sand for copepod to live and hide in, therefore giving them the best chance of reproducing successfully and continuously.

If you are ever concerned that your Mandarin is not eating enough or if it seems to be losing weight then simply add live copepods.  These can either be bought online or at your local fish shop (lfs).  

You can add copepods every 2 – 3 weeks.  There is no harm in this whatsoever but it will give you peace of mind that your Mandarin fish isn’t starving.

How do I know if I have copepods?

The best time to see copepods in your display tank is at night.  If you shine a light from a torch or mobile phone, you should be able to see hundreds of little moving dots on the glass, sand and rocks.  

In the refugium, turn the light off for a few minutes and then when you turn the light back on again you should see the copepods swimming around or on the side of the glass.  

Here is a video of the copepod in my refugium:

How to add copepods to a saltwater tank

Main Display Tank:

Unless you are wanting to feed your saltwater fish copepods, then you will need to wait until evening to put them in your main display tank.  If you place them in the tank during the day, very few copepod will have the chance to escape and settle in the rocks and sand. 

Turn off all wavemakers/powerheads and using a turkey baster, release the copepods onto the rocks and sand.  After roughly 10 minutes, turn everything back on again.

You can do this process several times until you are sure you have a thriving copepod population able to sustain itself.  

Refugium:

If copepods are intended for your refugium then they can be released at any time.  

Brine Shrimp

Newly hatched brine shrimp are considered extremely nutritious.  However, it needs to be stressed that these should not be the sole source of food for fish such as the Mandarin fish.  They can be used to supplement their diet but they need a thriving copepod population to sustain them long term.

It is really easy to hatch brine shrimp from eggs and you only need a few items and a small space on a shelf to do so.  Eggs are available either online or at your lfs.  

SEE HOW EASY IT IS TO HATCH BRINE SHRIMP HERE!

DIY Mandarin Feeding Station for Brine Shrimp

A feeding station is used to introduce live newly hatched brine shrimp into your tank at a slower rate.  Mandarin Fish are slow deliberate feeders and this feeder allows them time to eat their fill without the shrimp all being swept away in the current.

How to make a DIY Mandarin Feeding Station

To make a Mandarin feeding station you will need the following:

Instructions:

1. Cut out the central part of the plastic container lid.

2. Cut a piece of stocking large enough to stretch over the top of the container.

3. Drill a hole into the side of the container and push part of the airline through, then superglue into place.  (I included a small length of acrylic in mine – only because I had it lying around but this is not necessary at all.)

4. Cut the end from the sealant nozzle ensuring the hole is large enough to push the airline through and superglue into place if needed.  Mine is a tight fit without the need to glue.

5. Make sure that the airline has enough length to extend from the feeding station to the water surface.

6. Place the lid on the container with the stocking held securely between them, and maneuver the feeder into position inside your tank. Use a plastic peg to secure the airline to the tank rim.

Pour the baby brine shrimp in through the nozzle at the top and watch the Mandarin have a feast!

The video below will give you an idea of how it all comes together.

Frozen Foods

Although there have been instances of Mandarin fish being trained to eat frozen mysis (mine will even chase frozen mysis around the tank at feeding time), there are still reports of dragonets dying when eating frozen food as the main part of their diet.  

The thinking behind this is that they are not getting their requirement of live food, which they have evolved to eat and therefore are not consuming the correct nutrients.  They are first and foremost foragers and rely on a diet which is made up mainly of Copepod.

There is certainly no harm however in getting your Mandarin fish to eat frozen food as long as it is only supplementing their Copepod diet and not using frozen food instead of it.  

If you would already have a Mandarin fish and would like to try and get it interested in eating frozen food, then please see below. 

How to get Mandarin fish to eat frozen food

Feeding a Mandarin fish frozen food can be hit and miss.  Each fish is different.  While one may take mysis, another may prefer blood worms or black worms.  

Try them one at a time and see which one your Mandarin fish prefers.

Method

Make sure to turn off all powerheads and gyres as the food won’t be washed away as quickly.  Place food for the rest of your fish in one side of the tank and then, using a turkey baster or syringe, place your food of choice (blood worm, white worm, mysis, blackworm etc.) throughout the tank.  

Spread the food in crevices and any nooks and crannies, especially where the Mandarin likes to spend a lot of time.  

Once you have found which food the dragonet will eat, then ideally do this twice a day.  

Just starting out in the saltwater hobby? Get your copy of How To Set Up A Successful Saltwater Aquarium ebook today.

This ebay will help to guide you past the mistakes I have made over the years.

Are Mandarin Fish Hard to Keep?

Mandarin Dragonets, also known as Mandarin fish, are known to be notoriously difficult fish to keep.  The reason for the difficulty is their preference for live food. 

Please be warned!  The keeping of these fish should only be attempted if you have all of the following:

It takes time to build up a sizeable population of copepods capable of sustaining the Mandarin fish’s diet.  In a newly cycled tank you can still get spikes in nitrite and ammonia and these spikes could kill off the entire copepod population.  This is why a mature system is essential.  It’s provides a stable habitat for copepod which turn can successfully feed a Mandarin fish.

Mandarin dragonets are foragers and basically search for food all day long, picking copepod off the rocks.  The more rock, the more surface area for the fish to graze. 

So there you have it!

To summarise, these are fantastic fish to keep, but they don’t come without a lot of work from your end!  Keeping of Mandarin fish is no easy task so think very carefully about the time you have to dedicate to it before rushing in and buying one.

Copepod populations can dramatically fluctuate in your tank.  My Mandarin thankfully likes a bit of frozen mysis too, but I still need to ensure that he has a constant supply of live food.  I always have to stay ahead of the game, concerned that he may starve should I not notice a decline of pods in my tank.

What Do Mandarin Fish Eat?