40 Gallon Breeder

40 Gallon Breeder is a 91.4 × 45.7 × 40.6 cm (36 × 18 × 16 in) aquarium, rated at 151 L (40 gal). Its footprint is 91.4 × 45.7 cm and the water stands about 34.6 cm deep once a 6 cm substrate layer is in — the two numbers that decide what you can plant in it and what you can stock it with.

Start a tank this size

At a glance

Size91.4 × 45.7 × 40.6 cm (36 × 18 × 16 in)
Volume151 L (40 gal), as sold
Water after substrateAbout 133 L (35 gal) with a 6 cm substrate layer
Footprint91.4 × 45.7 cm (36 × 18 in)
Water depth34.6 cm (13.6 in)
Substrate neededAbout 25 L for a 6 cm layer

Before it goes in

  • 40 Gallon Breeder is 91.4 × 45.7 × 40.6 cm (36 × 18 × 16 in) — rated at 151 L (40 gal), and roughly 133 L (35 gal) of actual water once a 6 cm substrate layer and the hardscape are in.
  • That layer takes about 25 L of substrate, which is what you order by.
  • 135 of the 160 animals in this library list a minimum tank at or under 151 L (40 gal). The biggest of them that still fit are Peacock Eel and Angelfish. Electric Yellow Lab and Siamese Algae Eater need more than this.
  • The water sits about 34.6 cm (13.6 in) deep over the substrate. Plants that get taller than that — Hygrophila corymbosa 'Siamensis' and Water Sprite — reach the surface and start growing along it, which is a look you either want or trim.
  • Its footprint is 91.4 × 45.7 cm, and that is the area a carpet has to cover — the number that decides how many pots you buy, not the volume.

What are its dimensions?

91.4 × 45.7 × 40.6 cm (36 × 18 × 16 in).

How much water does it hold?

It is sold as 151 L (40 gal), and roughly 133 L (35 gal) of actual water once the substrate is in. Stocking works off the second number; minimum-tank-size advice works off the first.

How much substrate does it take?

About 25 L for a 6 cm layer.

What fits in it?

135 of the 160 animals in this library list a minimum tank at or under its volume, and the water depth of about 34.6 cm sets which plants can grow without reaching the surface.

What fits in it

Often compared with

40 Gallon Breeder75PJuwel Rio 125
Size91.4 × 45.7 × 40.6 cm75 × 45 × 45 cm81 × 36 × 50 cm
Volume151 L152 L125 L
Footprint91.4 × 45.7 cm75 × 45 cm81 × 36 cm
Water depth34.6 cm39 cm44 cm

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