Step By Step Pygmy Corydoras biotope

I had an empty 45cm (18") aquarium which I wanted to create a biotope aquarium in. I was thinking about which small 'nano' fish to showcase in a natural aquarium. I got to thinking about pygmy corydoras (Gastrodermus pygmaeus, formerly Corydoras pygmaeus) one of the small dwarf species from the Corydoradinae family.

 

My friend Lianny inherited a group of about 15 from me a few years ago, but they are never that visible in her 100-litre (22 gal) planted aquarium. Perhaps a tank built specifically for these little fish, where they are the focal point, would be the best way to see them. 

I had also recently inherited some mature peace lilies (Spathiphyllum sp.) from Aquarium Gardens, and they would be perfect for replicating the marginal plants that these corydoras often associate with in the wild. An image of a simple biotope aquarium soon formed and I got to work recreating my vision. 

 

Step by Step Madeira River Biotope

Step 1 

The tank is cleaned and a light background installed. This will enhance the glow of the tannins, but a black background would work just as well for this biotope. 

 

Step 2

An orange sand is added and sculpted to be shallower at the front. I chose this colour as it will contrast nicely with the dark green leaves of the peace lilies. 

 

Step 3

For this aquarium I planed to reuse old pieces of hardscape. This piece of aquarium wood stood out to me, so I placed this in first and built the rest of the hardscape around it. 

 

Step 4

More wood was added until I had built a tangled network across the back of the tank. This left a gap at the front which the pygmy corydoras will hopefully use to swim in midwater. 

 

Step 5

Plastic plant pots were attached to the back glass using the suction cups provided, ensuring the top of the pot was level with the intended water line. The peace lilies were then planted into the pots and as their roots grow, they will help to hide the black plastic. Many other houseplants can work brilliant growing out the top of aquariums, too. 

 

Step 6

With the scape finished, it was time to fill the tank with dechlorinated tap water and some concentrated tannins to mimic the blackwater appearance. The tank clouded initially, but this soon cleared.  

 

The finished biotope

Once the tank had matured, the pygmy corydoras were added to their home. A reptile fogger added extra ambience to the display. 

 

Photo by Shutterstock

Pygmy Corydoras Fact File

Scientific name: Gastrodermus pygmaeus

Size: Up to 3cm (1.2”).

Origin: Recorded in Rio Maderia in Brazil, Rio Aguarico and Rio Napo in Ecuador and the Rio Nanay in Peru.

Habitat: Slow moving and still waters with a soft sandy substrate and cover in the form of roots, twigs and marginal plants.

Tank size: 45x30x30cm (18x12x12”)

Water requirements: Soft and acidic is ideal, but a pH between 6 and 7.4 and below 15°H will work for this species.

Temperature: 22-26°C (72-79°F)

Temperament: Peaceful and gregarious and will be more outgoing when in large groups. Due to their small size tank mates need to be carefully chosen as they can easily be outcompeted.

Feeding: Unfussy, but any foods must be small enough for their tiny mouths. Crushed flake and micro granules work well as do small frozen and live foods like baby brine shrimp.

Availability & cost: Fairly common, they are even available in an albino form in the trade. Expect to pay upwards of £3.50 each. 

 

Final Thoughts on my Pygmy Cory Biotope

The corys soon began to forage in the sand and rummage amongst the roots after being added to the aquarium. They were not shy, nor where they difficult to see, a stark contrast to how this species behaved in a busier community. When they weren't looking for food, they would zoom back and forth across the dark waters.

I stocked a handful of ruby tetras (Axelrodia riesei) alongside them for company. While not biotope correct, their small size makes them suitable tank mates for these tiny corydoras. Pencilfish could also make a great option, with Nannostomus eques hailing from Rio Madeira being the obvious choice. 

The reptile fogger gave the whole scene a soft, warm and mysterious vibe, while the outsized character and charm of the corydoras brought a smile to my face regularly. 

If you liked this article, check out Tai's step by step Brazillian tetra biotope!