Lemon Tetra

Where they come from

Lemon tetras come from Brazil, mostly slower-moving tributaries and backwaters where the water’s often tea-colored from leaves and wood. Think warm, soft-ish water, subdued light, lots of plants and roots to weave through.

Setting up their tank

Lemon tetras are beginner-friendly, but they’re at their best in a group. Give them swimming room across the front, and cover the back/sides with plants so they feel secure. A bright, bare tank tends to make them wash out and act jumpy.

• Tank size: 15–20 gallons works for a proper group; bigger is always easier
• Group size: aim for 8–12 if you can—6 is the bare minimum
• Temp: 74–80°F (23–27°C)
• pH: roughly 6.0–7.5 (they’re flexible if you keep it stable)
• Hardness: soft to medium is easiest
• Flow: gentle to moderate; they don’t need a river tank

Filtration-wise, any decent sponge filter or HOB works. I like a prefilter sponge on intakes—keeps them safe and gives you extra bio-filtration. Add a couple pieces of wood and some broad-leaf plants (crypts, swords) and you’re basically done.

What to feed them

They’re easy eaters. In my tanks they go nuts for small foods and do best when you rotate a few options instead of one flake forever. Their mouths are small, so think “tiny bites.”

• Daily staple: quality micro pellets or a fine flake
• Color/condition boosters: frozen daphnia, baby brine shrimp, cyclops
• Occasional treats: bloodworms (not every day), live baby brine if you have it
• If food is too big: crush it between your fingers before feeding

Behavior and tankmates

Lemon tetras are classic peaceful schoolers. They’ll do little sparring displays—especially males—but it’s usually just posturing. The bigger the group, the less any one fish gets singled out, and the more natural their schooling looks.

• Great tankmates: corydoras, small plecos, otos, kuhli loaches, rasboras, other peaceful tetras
• Good “centerpiece” fish: honey gourami, small/peaceful apistos (in a roomy tank), dwarf cichlids with mellow temperaments
• Use caution: fin-nippers (some barbs), super boisterous fish, or anything big enough to see them as snacks

Breeding tips (if you want to try it)

They’re egg scatterers, and adults will happily eat the eggs, so you need a little setup if you actually want fry. It’s a fun project if you like tinkering, but not something you’ll accidentally pull off in a community tank.

• Use a small breeding tank (5–10 gallons) with a sponge filter
• Add a spawning mop or a thick clump of fine plants (java moss works great)
• Dim lighting helps—cover the sides if the room is bright
• Condition with live/frozen foods for a week
• Move in a pair or a small group in the evening; spawning often happens early morning
• Pull the adults after you see spawning activity or eggs

Once the fry are free-swimming, start with infusoria/microworms if you have them, then baby brine shrimp as soon as they can take it. Clean water matters a lot at this stage—tiny daily top-offs or small water changes beat big swings.

Common problems to watch for

Most issues I’ve seen with lemon tetras come down to stress from a too-bright/too-bare setup, or water quality slipping in a small tank. They’re hardy, but they don’t hide problems well—if something’s off, you’ll see it in their color and posture.

• Washed-out color or hiding: usually too much light, not enough cover, or not enough fish in the group
• Clamped fins / hanging near the surface: check ammonia/nitrite first, then temp and oxygenation
• White spots (ich): often shows up after a temperature swing or new fish introduction
• Sudden aggression/nipping: small group size, cramped tank, or uneven feeding
• Bloated fish: overfeeding or too many rich foods—back off and offer daphnia

One last practical thing: quarantine new fish if you can. Lemon tetras are usually tough, but they’re often sold pretty young, and a simple quarantine saves you a ton of headache with ich and bacterial stuff later.