Hung's silvermouth cardinalfish

Where they come from

Hung's silvermouth cardinalfish (Jaydia hungi) comes out of the Indo-West Pacific scene, showing up around reefy coastlines where there are lots of hiding spots and broken-up light. Think rubble zones, crevices, and areas where a small fish can hover and disappear fast. That background explains pretty much everything about how they act in our tanks: they like cover, they like calm, and they do not love being the center of attention.

Setting up their tank

If you want Jaydia hungi to settle in, build the tank around security. They are not a "bare box" fish. A rockscape with caves, overhangs, and shaded pockets makes a bigger difference than chasing a perfect number on a test kit.

I have the best luck with them in a mature, stable reef or reef-like system where pods and microfauna exist and the fish are not getting blasted by random swings. They are labeled advanced for a reason: they can be touchy shippers, picky eaters at first, and they do not handle constant harassment well.

• Tank size: I would treat 30+ gallons as a starting point for one, and bigger if you plan a group or have other fish that move a lot.
• Aquascape: lots of crevices and at least a couple of "deep" hiding spots they can fully back into.
• Flow: moderate overall, but give them calmer zones behind the rockwork where they can hover without fighting current.
• Lighting: they do fine in bright reefs, but they use shade. Add overhangs or taller rock to create it.
• Filtration: run it like you would for a lightly stocked reef - steady, clean, and not neglected.

What to feed them

These are small predators that want meaty foods. The main trick is getting them confidently eating in your tank before bolder fish steal everything. Once they are trained, they usually become solid eaters.

• Best starters: enriched frozen mysis, finely chopped krill, calanus, and good marine frozen blends
• If they are stubborn: live enriched brine to kickstart feeding, then mix in frozen as they strike
• Once settled: small sinking pellets and soft granules can work, but do not expect pellets to be day-1 food

Feed smaller portions more often if you can. Two small feedings beats one big dump, and it keeps them from getting outcompeted.

How they behave and who they get along with

Jaydia hungi is a classic cardinal vibe: hovering, watching, and moving in short bursts. They are not aggressive bruisers, but they are not fearless either. Most problems come from tankmates that are too fast, too pushy, or too food-focused.

• Good tankmates: peaceful gobies, blennies, smaller wrasses that are not maniacs, reef-safe dwarf angels with decent manners, and calm clownfish pairs (depends on the clowns)
• Use caution: dottybacks, big damsels, large hawkfish, or anything that treats the whole tank like its personal gym
• Avoid: predators that can swallow them, and overly aggressive feeders that vacuum the water column in 10 seconds

They can be kept with other cardinals, but expect some posturing if space is tight. If you try a small group, give them more rockwork than you think you need so subdominant fish are not stuck in the open.

Breeding tips

Like a lot of cardinalfish, Jaydia species are mouthbrooders (the male typically holds the eggs). In a calm tank with a well-matched pair, you may see the male stop eating and hang back while he carries. That is your clue.

• Conditioning: feed heavy on small meaty foods (mysis, calanus, finely chopped seafood) and keep stress low
• Pair dynamics: give them multiple hiding spots so one fish cannot constantly bully the other
• If the male is holding: do not keep "checking" on him with lights and netting - he can spit the clutch

Common problems to watch for

Most failures with Jaydia hungi come down to three things: shipping stress, refusing food early on, and getting bullied into hiding. If you handle those, the rest is normal marine fishkeeping.

• Not eating in the first week: try live enriched brine as a bridge, reduce competition at feeding time, and give them cover and shade
• Getting outcompeted: target feed and consider rearranging rock or rethinking tankmates
• Ich/velvet risk: they are not uniquely immune. Quarantine is your friend, especially because stress makes outbreaks hit harder
• Slow decline in "too clean" or sterile systems: some individuals seem to do better once a tank is mature and food options are varied