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Collett’s Tetra: A Comprehensive Guide (Moenkhausia collettii)

The Collett’s Tetra (Moenkhausia collettii) is one of those fish that doesn’t get talked about nearly enough in the hobby. It’s not flashy in the way neon tetras are, and it doesn’t have some wild gimmick—but once you actually keep them, you realize how good they are.

This is a clean, classic tetra. Subtle silver body, a bit of sheen, nice movement, and that tight schooling behavior that just makes a tank feel alive. They’re the kind of fish that doesn’t scream for attention—but somehow ends up being one of your favorites anyway.

If you’re into natural-looking aquariums or just want something a little different from the usual tetra lineup, this is a seriously underrated option.

Natural Distribution & Habitat

Moenkhausia collettii comes from South America, mainly in Amazonian and Orinoco-type systems.

In the wild, they’re found in:

  • Slower tributaries
  • Floodplain areas
  • Calm river edges

Think:

  • Slightly tannin-stained water
  • Sand or fine substrate
  • Wood, roots, and leaf litter
  • Moderate plant cover

They’re not from extreme blackwater, but they definitely lean toward that soft, natural river look.

Size

They stay a really nice, manageable size.

  • Adult size: about 2–2.5 inches

Big enough to be noticeable, small enough to keep a solid group without needing a massive tank.

Aquarium Care

These are easy fish to keep, and honestly pretty forgiving.

  • Tank size: 20 gallons minimum (but 30+ is way better for a proper group)
  • Setup: Plants, wood, and open swimming space
  • Substrate: Sand or fine gravel
  • Lighting: Moderate (they look better with slightly subdued lighting)

They really shine in a tank that isn’t overly bright or sterile. Add some wood, maybe a few botanicals, and suddenly they just look right.

And like most tetras:

👉 Keep them in a group — I’d say at least 8–10, but 12+ is where they really start to look good.

Water Parameters

Nothing crazy here—pretty standard tetra stuff.

  • Temp: 74–80°F
  • pH: 6.0–7.5
  • Hardness: Soft to moderate

They’ll adapt to typical community tank conditions, but like most South American fish, they definitely look and act better in slightly softer, stable water.

Diet

Super easy to feed.

They’ll take:

  • Flake
  • Small pellets
  • Frozen foods (brine shrimp, daphnia, bloodworms)
  • Live foods if you’re feeling fancy

If you want them to really pop and stay active, mix in some frozen or live food a few times a week.

Behavior & Tank Mates

This is where they really win.

They’re:

  • Peaceful
  • Active
  • Tight schoolers (especially in bigger groups)

Great tank mates:

  • Other tetras
  • Rasboras
  • Corydoras
  • Apistos or other dwarf cichlids

They hang mostly in the midwater, constantly moving but not chaotic—just a nice, steady presence in the tank.

Breeding

Not something most people are doing with this species, but they follow the typical tetra pattern.

  • Egg scatterers
  • No parental care
  • Eggs laid in plants or fine structure

If you’ve bred other tetras, the approach is basically the same—soft water, dim light, and separating adults from eggs.

Fun Facts & Hobby Notes

They’re better than they look in photos.
Seriously—this is one of those fish that doesn’t photograph well but looks great in person.

They give a “natural” feel to a tank.
If you’re trying to build something that looks like a slice of a river instead of a display tank, these fit perfectly.

They’re not overbred.
Which honestly shows—good behavior, solid health, no weird quirks.

They school tighter than a lot of common tetras.
Especially when kept in bigger groups.

Why Aquarists (Quietly) Love Them

This is one of those fish that doesn’t get hyped—but people who keep them tend to stick with them.

Why?

  • Clean, natural look
  • Great schooling behavior
  • Easy to care for
  • Works in almost any peaceful setup
  • Something different from the usual tetra lineup

They’re not a “wow” fish at first glance… but they’re the kind of fish that makes your tank feel complete.

Looking to Add Fish to Your Aquarium?

If you're looking to add new fish to your aquarium, we recommend purchasing from trusted retailers known for their healthy livestock and excellent selection. The Wet Spot Tropical Fish has one of the best selections of rare and high-quality freshwater fish in the hobby, with excellent shipping and consistently healthy stock. Moonlight Aquatics is another fantastic source, especially for uncommon species and great prices on unique fish you don’t see everywhere. If you’re looking to add shrimp to your tanks, Buy Pet Shrimp specializes in hardy, well-bred freshwater shrimp that ship safely and arrive in great condition.

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Tetra Fish: A Comprehensive Guide to the Characin Fishes of the Aquarium Hobby

 

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