Tchefou cardinalfish

Where they come from

Tchefou cardinalfish (Jaydia tchefouensis) are a small Indo-Pacific cardinalfish that show up around reefs and sheltered coastal areas. Think dusk-and-shadow fish: they like hanging back in cover and picking food out of the water column rather than being out front like anthias.

They are not as commonly kept as Banggais or pajama cardinals, which is part of why they land in the advanced bucket. Most of the challenge is getting them eating well and keeping them calm long-term.

Setting up their tank

If you set these up like a typical bright, open reef display, you will spend weeks wondering why you never see them and why they look skinny. Give them shade, places to hover, and a tank that is already settled in.

• Tank size: 20-30 gallons for a single or a bonded pair, 40+ if you want to try a small group
• Aquascape: lots of rockwork with overhangs, caves, and branching structure they can sit under
• Lighting: they do better with moderate light and shaded zones (floaters are not a reef option, so use rock shadows and lower PAR areas)
• Flow: moderate, not a blasting gyre aimed at their favorite hideout
• Filtration: stable, mature biofilter and decent export since you will be feeding heavier than you think

Keep parameters boring and steady. Reef range salinity (around 1.025-1.026), temp in the mid-70s to upper-70s F, and avoid big day-to-day swings. They handle a lot less drama than some hardier cardinals.

What to feed them

These are small-mouthed, bite-sized predator fish. In my tanks they did best when I fed like I was keeping finicky anthias: small portions, more often, and with the right particle size.

• Go-to frozen: mysis (smaller pieces), enriched brine, calanus, finely chopped krill, and good marine mixes
• Live foods for new/skinny fish: live brine (enriched), copepods, or blackworms (rinse well and use sparingly in marine)
• Dry foods: small sinking pellets and soft micro-pellets once they recognize food as food

New arrivals often act like they are eating but spit things out. If you see that, switch to smaller items (calanus and chopped mysis) and try mixing in a little live food for a week to get them rolling.

How they behave and who they get along with

Classic cardinalfish vibe: they hover, they lurk, and they get bold mostly at feeding time or as the lights ramp down. They are not showy swimmers, but they are really cool if you like subtle behavior and that calm, suspended-in-space look.

Temperament is generally peaceful, but they can be pushy with their own kind in tight quarters. In groups, you will often see one fish get kept in the worst corner if the tank is too small or too open.

• Good tankmates: gobies, blennies, smaller wrasses that are not hyper-aggressive, clownfish (usually), peaceful tangs in larger tanks
• Use caution with: dottybacks, larger hawkfish, aggressive damsels, big wrasses, and anything that treats small fish like snacks
• Inverts: generally reef-safe, but very small shrimp (tiny sexy shrimp, newborn cleaners) can look like food to some individuals

Breeding tips

Like a lot of cardinalfish, Jaydia species are mouthbrooders. If you keep a compatible pair well-fed and low-stress, you may see the male holding eggs or larvae (he will look like he has a mouthful of marbles and he will stop eating).

• Give them privacy: calm tank, dimmer zones, and minimal chasing from tankmates
• Feed up before a hold: frequent small meals and varied frozen foods for a few weeks
• If the male is holding: do not pester him, and keep hands out of the tank as much as possible
• Raising fry: you will need a separate plan (rotifers/copepods and appropriately sized foods). This is where it gets advanced fast.

Common problems to watch for

Most issues I have seen with these come down to stress and food. They can look fine for a week or two and then slowly fade if they are not really getting enough to eat.

• Refusing food or spitting: often particle size or stress from bright light/too much activity
• Getting skinny while "eating": they are being outcompeted or only grabbing low-calorie scraps
• Crypt/velvet risk: many cardinals arrive with parasites. Quarantine and observation go a long way
• Bacterial issues after shipping: frayed fins, cloudy eyes, or lethargy in the first two weeks
• Jumping: they can launch when spooked, especially at night

My rule with this species: if they are not visibly filling out by week two, change something. Dim the area they hang in, slow down the feeding competition, and switch to smaller, richer foods. Once they settle and associate you with dinner, they get a lot easier.