At a glance the quick version
Looks how to spot one
Small scaleless dragonet
A small, rounded bottom fish with no scales, covered instead by a slime coat. Its body is a maze of electric blue, orange and green swirls, and males carry a taller first dorsal fin.23
Personality what they are like
Gentle and unhurried with other species, but males are usually not tolerant of each other.3
Daily activity how busy a day looks
Spends the day slowly working over rock and sand, picking off tiny prey one bite at a time, and uses its large pelvic fins to walk along the bottom.2
Grooming and care the hands-on bits
Needs a mature tank with plenty of live rock and live sand that already supports a healthy population of tiny crustaceans for it to graze on.32
Home where they are happiest
Minimum about 30 US gallons (114 L), well established, with live rock, live sand and hiding spots. Wild fish live in sheltered lagoons and inshore reefs with silty coral rubble at 1 to 18 m.31
Food basics what goes in the bowl
Feeds on tiny live prey such as copepods and amphipods, plus small worms and snails. In aquariums it grazes the natural fauna and may learn to take live or frozen foods.23
Company who they like around
Lives in small groups in the wild. In aquariums it gets along with other kinds of fish but is usually not tolerant of its own kind, so one per tank is the safe choice.13
The story where it all began
Albert Herre described it from the Philippines in 1927 as Callionymus splendidus; it was later moved to Synchiropus. It is now well known in the aquarium trade and has been bred in captivity.21
Fun facts for the dinner table
- 1
It is one of only two known vertebrates that make blue colour with true blue pigment cells instead of light-scattering structures.2
- 2
Instead of scales it wears a slippery slime coat.2
- 3
Mating pairs rise together toward the surface in close contact to release their eggs.1
- 4
Synchiropus is Greek for 'together hand-foot', and splendidus is Latin for 'bright' or 'glittering'.2
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 2018)1
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Mandarin Dragonet. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Salinity checkevery week
- Top-upTop up evaporation with fresh RO water, not salt waterevery day
- Water testevery week
- Water changeAbout 10 to 20% of the waterevery 2 weeks
- Glass cleanevery week
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- FishBase: Synchiropus splendidus fishbase.seused for distribution, size, depth, habitat, spawning, IUCN
- Wikipedia: Mandarinfish (Synchiropus splendidus) en.wikipedia.orgused for other names, colours, diet, history, pigment and slime facts
- LiveAquaria: Green Mandarin liveaquaria.comused for care, tank size, temperament, diet, colours
Checked 2026-09-30. Text is written in our own words from these sources.