Green chromide

1) Where they come from

Green chromides (Etroplus suratensis) are from southern India and Sri Lanka, hanging out in estuaries, backwaters, and coastal lagoons where fresh and saltwater mix. They’re basically "brackish cichlids" that have been dealing with changing salinity forever, which is why they’re so much happier in lightly salty water than in plain freshwater long-term.

2) Setting up their tank

Think bigger than you first want to. These fish aren’t tiny once they settle in, and they’ve got that cichlid confidence. If you’re keeping a small group, a 75g/280L is a comfortable starting point, and bigger is always easier on everyone’s nerves.

I’ve had the best luck keeping them in brackish water with marine salt mix (not aquarium “tonic” salt). Aim for a low-to-mid brackish feel rather than full marine. Stability beats chasing numbers.

• Tank size: 55g/200L minimum for a pair; 75g+ for a group
• Salinity: low–medium brackish (around SG 1.005–1.012 is a nice range)
• Temp: mid/upper 20s °C (about 24–28°C / 75–82°F)
• pH/hardness: they like it alkaline and harder rather than soft/acidic
• Filtration: strong bio + good flow; they eat well and make real waste

Decor-wise, you’re balancing two things: giving them places to get away from each other, and leaving open swimming space. I like using rounded rocks, driftwood, and tough plants (or just commit to a mostly hardscape setup). They will graze and pick, and delicate plants usually get shredded or uprooted.

• Use rock piles/wood to break line-of-sight (cuts down chasing)
• Leave a wide open area in the middle for cruising
• Substrate: sand or fine gravel; they’ll sift and mouth it
• If you want plants: try Java fern/Anubias attached to wood/rock; expect some nibbling

3) What to feed them

They’re enthusiastic eaters and they’ll act like they’re starving 24/7. The trick is keeping the diet varied and not going too heavy on fatty, meaty foods. In my tanks, they do best with a “mostly quality pellets + veggie” routine, then treats on top.

• Staple: good cichlid pellets or spirulina-based pellets
• Veggie rotation: blanched spinach, zucchini, shelled peas (great for clearing them out)
• Protein treats: mysis, brine shrimp, chopped prawn—small amounts
• Grazing bonus: algae wafers or spirulina flakes now and then

Feed smaller portions 1–2 times a day, and watch their bellies. If they start looking thick behind the head or stringy poop shows up, back off and do a veggie day.

4) Behavior and tankmates

They’re cichlids, but not the “murder everything” type… until breeding mood hits. Day to day, a group can be pretty social, with a pecking order and some jawing. During spawning they flip the switch and suddenly that calm fish is patrolling half the tank like it owns the deed.

I’ve found they’re easier in groups (5–7) if your tank is big enough, because the aggression gets spread out. A lone pair in a smaller tank can hyper-focus on each other or on tankmates.

• Best vibe: a roomy tank with a small group and lots of sight breaks
• They will dig, redecorate, and “taste test” anything that sits still
• Expect occasional lip-locking and fin posturing—normal cichlid politics

Tankmates that can work are other sturdy brackish fish that aren’t tiny or timid. Avoid very small fish (they’ll get bullied) and slow, fancy-finned fish (they’ll get nipped). Also skip delicate bottom dwellers unless you’re 100% sure they tolerate your salinity.

• Often works: archerfish (in big setups), monos/scats (again, big setups), some brackish gobies, larger mollies in lower brackish
• Use caution: puffers (temperament roulette), small schooling fish (stress magnets)
• Usually a bad time: fancy goldfish, delicate tetras/rasboras, long-finned fish

5) Breeding tips

They’ll breed in aquariums if they’re happy, and it’s honestly pretty fun to watch. They’re substrate spawners and both parents get involved—cleaning a site, laying eggs, fanning, then herding the fry like tiny sheepdogs.

If you want babies, give them flat rocks or slate tiles and keep the tank stable. Sudden big changes (especially salinity swings) can make them eat the spawn or abandon it.

• Provide: flat stone/slate + some privacy
• Keep: steady brackish salinity and consistent temps
• Expect: aggression spike—move tankmates or use dividers if needed
• Fry food: newly hatched brine shrimp and crushed pellets once they’re big enough

6) Common problems to watch for

Most “mystery” issues I’ve seen with Green chromides come down to two things: messy water from heavy feeding, and salt done inconsistently. They’re hardy, but they don’t love rollercoaster conditions.

• Bloat/constipation: usually from rich foods or overeating—add veggie days and reduce feeding
• Fin nipping and stress: not enough space/sight breaks, or a breeding pair policing the tank
• Ich/white spot: can happen, especially after new fish—quarantine helps a ton
• Poor long-term health in freshwater: they often look “fine”… until they don’t. Low brackish suits them much better

If your fish are hiding, darkening, or clamping fins, look at the basics first: ammonia/nitrite, nitrate, and whether your salinity has drifted. I keep a refractometer around—hydrometers can be “close enough” until they’re not.