Indian perch
Jaydia lineata
Indian perch (Jaydia lineata) exhibits a streamlined body with distinct vertical stripes and a silvery hue, enhancing its camouflage in freshwater habitats.
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About the Indian perch
Jaydia lineata is a little Indo-West Pacific cardinalfish with a clean set of brown vertical bands and that classic big-eyed, hang-back cardinalfish vibe. The really cool part is the breeding - the male mouthbroods the eggs, so if you ever got a pair settled in, you could actually see some neat parental care behavior.
Also known as
Quick Facts
Size
14.8 cm
Temperament
Peaceful
Difficulty
Intermediate
Min Tank Size
30 gallons
Lifespan
3-5 years
Origin
Indo-West Pacific
Diet
Carnivore - small crustaceans and meaty frozen foods (mysis, brine shrimp), plus small pellets
Water Parameters
23-28°C
8-8.4
8-12 dGH
Need a heater for this species?
This species needs 23-28°C in a 30 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Give them a dim, cavey setup - overhangs, rock piles, and shaded corners - because they hang back in the water column and spook under bright lights.
- Keep them in full marine saltwater: 1.023-1.026 SG, 24-27 C (75-81 F), pH 8.1-8.4; they hate swings, so top off daily to stop salinity creep.
- They do way better in a small group (3-6) than solo, but add them together and provide multiple hiding spots so one fish does not claim the whole cave.
- Feed after lights go down if you can - mine were boldest at dusk; start with frozen mysis, enriched brine, and finely chopped shrimp, then mix in small sinking marine pellets once they recognize food.
- Tankmates: calm reef fish work (gobies, blennies, cardinals, chromis, peaceful wrasses); skip bullies like dottybacks and big damsels, and do not keep tiny shrimp or nano fish they can swallow.
- They are mouthbrooders (the male carries the eggs). If you see a male holding (swollen jaw) and not eating, minimize stress and avoid netting/chasing; incubation can last multiple weeks before release.
- Watch for them wasting away from not getting enough food in busy tanks - they are slow, polite eaters, so target feed with a pipette and make sure they actually swallow.
Compatibility
Good Tankmates
- Other small, peaceful reef fish that mind their own business - think pajama/cardinalfish, small chromis, or similar calm schooling types. Indian perch are pretty chill and do better when the vibe stays mellow.
- Clownfish (the more laid-back ones) in a normal reef setup. They usually ignore the Indian perch, and the perch just hangs in the water column and cruises at feeding time.
- Small gobies and blennies that perch on the rocks or sift sand - watchman gobies, neon gobies, tailspot blennies. Different zones, no drama.
- Firefish and other gentle dartfish. They are both on the shy side, so give them rockwork and not-too-crazy tankmates and they settle in fine.
- Reef-safe wrasses that are on the calmer end (fairy wrasses, flasher wrasses). As long as the wrasse is not a bully, they coexist great and eat similar foods.
- Peaceful tangs or rabbitfish in bigger tanks (one of the smaller tangs, or a foxface). They are active but not usually predatory toward a full-grown Indian perch, and they keep to themselves.
Avoid
- Aggressive or territorial fish like dottybacks, damsels with an attitude, and most hawkfish. They love to push shy fish around, and Indian perch will just get stressed and stop coming out.
- Big-mouthed predators - groupers, lionfish, larger scorpionfish, and many eels. If it can fit the perch in its mouth, it will eventually test that theory, especially at night.
- Triggerfish and most puffers. Even if they do not straight-up eat them, the constant pecking/nipping and chaos is rough on a peaceful, midwater fish like this.
Where they come from
Indian perch (Jaydia lineata) is one of those small cardinalfish from the Indo-West Pacific. Youll see them around reefs and sheltered coastal areas, usually hanging in the shade or tucked near structure during the day, then getting bolder at feeding time. That whole "hide in the dark, rush the food" vibe pretty much carries over into the aquarium.
Setting up their tank
Think "small, calm reef fish" more than "open-water swimmer." Mine settled fastest in a tank with lots of broken-up sight lines: rockwork caves, overhangs, and a few darker corners. If the tank is bright and bare, theyll act jumpy and spend all day wedged behind a pump.
- Tank size: 20-30 gallons works for a small group, bigger is easier if you want tankmates
- Keep them in a group if you can (3-6). Singles can get timid and picky
- Rockwork with caves/ledges. They like to hover under cover
- Moderate flow, not a blasting gyre aimed at their favorite hideout
- Stable marine salinity (around 1.025) and typical reef temps (mid 70s F)
Give them a predictable "safe zone". A shaded overhang or a little cave that isnt right in the main current makes a huge difference in how quickly they start coming out to eat.
They can jump, especially the first week or two. A tight lid or mesh top will save you a bad morning.
What to feed them
These are small-mouthed carnivores. Theyre not complicated, but they can be stubborn about dry food at first. Once they learn the routine, they turn into little pigs at feeding time.
- Best starters: frozen mysis (smaller pieces), finely chopped krill, brine shrimp (enriched if possible)
- Great variety: calanus, copepods, finely chopped clam/squid, small marine pellets once trained
- Feed small amounts 1-2 times a day. They do better with frequent small meals than one big dump
- If you have fast tankmates, use a turkey baster to target-feed near their hangout
If they ignore pellets, dont panic. Get them eating frozen confidently first, then mix in a few pellets with the thawed food. After a couple weeks most will take prepared foods without drama.
How they behave and who they get along with
Jaydia lineata is generally peaceful and a bit shy, especially in bright tanks. In a group they act more natural: hovering together, then fanning out to grab food. You might see some pecking and posturing, but its usually just sorting out personal space.
Tankmate-wise, pick calm fish that wont outcompete them or bully them out of their hiding spots. Theyre also bite-sized to a lot of predators, so think carefully before mixing them with anything that has a big mouth.
- Good tankmates: gobies, blennies, firefish, small wrasses that arent hyper-aggressive, peaceful damselfish (careful, some are jerks), reef-safe inverts
- Be careful with: super fast eaters (chromis can outcompete them), nippy fish, aggressive dottybacks
- Avoid: lionfish, large hawkfish, groupers, big wrasses, and anything that could swallow them
If your Indian perch always stays hidden and looks skinny while other fish look fat, its almost always a feeding competition issue. Target-feed them for a while and watch their bellies after meals.
Breeding tips
Like a lot of cardinalfish, theyre mouthbrooders. In home tanks its possible but not something youll stumble into every week. If you do see breeding behavior, its usually a pair getting tighter and the male holding eggs in his mouth for a while.
- Keep a small group and let a pair form naturally
- Feed heavier and with more variety to condition them
- If you spot a male mouthbrooding, keep the tank calm and avoid chasing him around
- Fry need tiny foods (rotifers/copepod nauplii) and a plan. Theyre not a "raise by accident" kind of baby fish
A mouthbrooding male often stops eating or eats very little. Thats normal. The trick is giving him peace so he doesnt spit the clutch from stress.
Common problems to watch for
Most issues Ive seen with this fish come down to stress and food. Theyre hardy once settled, but the first couple weeks are the make-or-break window.
- Refusing food: common after shipping. Start with small frozen foods, dim lights for a day or two, and feed near their shelter
- Getting picked on: theyll clamp fins and hide constantly. Rearrange rockwork or remove the bully
- Skinny fish in a community tank: outcompeted at feeding time. Target-feed or add a second feeding
- Crypt/velvet risk: like most marine fish, they can bring or catch parasites. Quarantine is your friend
- Jumping: especially during acclimation or after a scare. Cover the tank
If you see rapid breathing, flashing, or a dusting/velvety look, dont wait it out. Thats one of those situations where acting fast saves the fish.
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