I love my Mandarin fish! I spend a lot of time checking him out. These fish have me convinced that it's the luck of the draw. I have a friend with a about 100 kg of live rock in their reef/fish tanks and can't keep one alive. I have 10 kg of live rock in my tank and my mandarin is going on his 6th month with no signs of hunger or stress. My father has a fish only tank with no live rock and kept a mandarin fish for two years running. It eats flake food, bloodworms and frozen brine. He has since gone back to fresh water and returned the fish to the store. So like I said it's the luck of the draw I guess, but if you want one in your aquarium I would make sure you have plenty of live rock and make sure your rock is producing lots of amphipods and copepods. (those little water flee type bugs that have big antenna and lots of legs). Mandarin fish are most happy when they hunt for their food and these are their main diet in the oceans. Or so I've read...
Because they are bottom dwelling, it can be hard to get food to them, especially in a large tank. They do not make much of an attempt to get the food at a higher level then they are.
I've had great luck feeding my mandarin mysis shrimp in my 75 liter. I have about 12 kg of live rock, with lots of caulerpa, which seems to also contribute to copepod populations.
This is the story of Simon:
I started out with a 40 liter aquarium with some live rock. The fish store sold me a psychedelic goby with the promise that he would do well as long as I had live rock because they are grazers of algae. When I brought him home I got on the internet to find out more about this beautiful creature and found out he was a psychedelic mandarin fish and eats little things called copepods. What a shock! So I had to find out what copepods are and where do I get them. After many phone calls and realizing I can't buy them from a store, my only source would be live rock (with the hope they were actually on the rock). After 5 months and a tank now over stocked with live rock, my poor fish (named Simon) was still not getting enough to eat. I tried brine shrimp, but they seem to swim to fast for Simon...so I was on a mission to find food. I refused to let Simon perish.
After some research about microscopic crustaceans I found a website which sold amphipods. This was good for about a month, but Simon ate them too fast for them to create a colony. Fortunately I live near the ocean and did some scavenging to see what critters I could find. Lots of good yummy crustaceans and lots of bad evil crustaceans. At least I was getting closer. This was great, but got old having to go to the ocean twice a week, not to mention it's in a bay which is really kind of stinky/dirty. I made a choice to get a bigger tank.
My apartment is rather small, so the largest tank I could go was 100 liters. I made sure it was long, shallow, and short to give Simon the max floor space, and allow for as much live rock without over packing the tank. I ended up with an acrylic tank and a Whisper Power Filter Model 1 which has a flow speed control (this came in handy later). 2 1/2 bags of live sand, plastic grid & plastic stilts (allows to give variety of height to your rocks without having to pile them on top of each other, and creates great hiding places underneath), about 8-10 kg of live rock and an order of 200 amphipods, lactuca (like lettuce) and caulerpa (tall seaweed like). The lactuca & caulerpa are for both food and shelter for the amphipods. My goal was to give my new tank a month to grow colonies of microscopic crustaceans. But Simon's tummy was sunken and he kept looking out longingly at the new tank, so I moved him over after only 1 1/2 weeks. It has been 2 months now and Simon is so fat! There is also an abundant supply of tiny white flea-like critters on the walls of the tank. It's a success!
Another great surprise occurred after I had recently purchased an arrow crab. Knowing the arrow crab eats brine shrimp I brought some home for him, I turned down the flow on the Whisper filter, added some brine shrimp, and Simon was actually eating them. With the water flow down really low the brine shrimp are able to settle in locations that a mandarin fish normally finds food. He will also eat some of the dead brine shrimp as well.
So for all those who want to enjoy this beautiful fish...here you go! Just be careful of what other fish/creatures you keep in the same tank as the mandarin fish so you don't deplete the food source.
I have a Mandarin fish. He is of wonderful colours and has a very interesting hovering habit. I have kept this mandarin fish for nearly 3 years. I would like to let you all in to my success with this fish. As mentioned, Mandarin fish do enjoy amphipods and other parasite sized organisms. However this is the natural diet of a Mandarin fish in the wild and one that will be replicated in the aquarium given a substantial source of food. I would definitely not strive to add amphipods etc to a reef aquarium. Only a set-up of live rock plagued with these minute creatures will offer anything close to what is available in the reef zones. Fish, despite some reports, have an instinctive memory that will guide them to a place of feeding once established. Small amounts of dead artimea (may be frozen) should be placed using syringe with tubing in an area at the side or back of rock work twice a week. The Mandarin fish will readily accept this nourishment when hungry and will return to this area (ideally a small crevice in the living rock) regularly to check up on food availability. If you have many other fish (as I do) it is necessary, as mentioned, to complete this feeding regime after lights out. I promise within a few weeks you will have a nice, plump Mandarin. Do not use a food soak, it will attract other fish.
I live in Melbourne Australia and recently purchase a 2nd hand, 5 foot saltwater aquarium. I decided to pay the local aquarium a visit, and on my many visits, I noticed a cute little Mandarin Fish in their large reef aquarium. When I got him home I allowed him to settle in and aquaint himself with Scoot my Scooter Blenny and Ivan my Coral Cleaner Shrimp. Two hours later, Scoot began to show signs of hunger, so I broke off a piece of Hikari Frozen Brine Shrimp. The pieces of shrimp broke up and floated right past the Mandarin's mouth, Scoot snapped it out from under him, this got our friend going and he immediately began chasing the floating Brine Shrimp. I switched off the powerheads, giving the shrimp time to settle on the aquarium floor. It was a race between Scoot, Ivan and the newcomer as to who would get the greatest share, and the Newcomer won. I've even tried him on bloodworms and his immediate reaction was to fan out his fins in excitement. This little guy will eat anything that looks edible and certainly gives the other two a run for their money.