Make your own breeding mop to breed danios and rice fish

Want to breed small schooling fish like danios or medaka without the parents eating their own eggs for breakfast? Then a breeding mop is your secret weapon. It's essentially just a bunch of yarn that mimics plants, but the fish feel like they're the perfect place to leave their eggs. Cheap, simple, and super effective. 🧶🐟

Why use a breeding mop?

Danios, rice fish, and similar species like to lay their eggs among fine-leaved plants. In a regular community tank, these eggs are often eaten within an hour. Using a breeding mop provides the eggs with a hiding place and allows you to easily remove them from the tank to raise them separately. This increases the chance of raising young fish instead of… just another snack for the parents. 😉

What do you need?

• Dark green or black acrylic yarn (not cotton, which rots in water)
• A cork or small polystyrene block as a float
• A pair of scissors
• A book or piece of cardboard about 15–20 cm wide
• A piece of fishing line or extra yarn to tie the bundle

Step-by-step guide

1. Wrap the yarn: Take a book or cardboard and wrap the yarn around it 50–80 times. The more turns, the fuller the mop.
2. Cut loose: Slide the bundle off and cut open one end. You now have strands of yarn.
3. Bundle: Tie the strands tightly together in the middle. It will now resemble a thick brush.
4. Attach the float: Secure the bundle to a cork or Styrofoam so it floats. Prefer a sinking mop? Leave the float off and weigh it down with a small stone.
5. Rinse: A quick rinse under the tap removes lint. Then the mop can go straight into your grow box.

How do you use a grow mop?

Place a group of adult fish in the breeding tank along with the mop. Females often stick their eggs between the strands in the morning. Then carefully remove the mop and place it in a separate container with gently aerated water. After 7–14 days, you'll see the first mini-fish emerge. 🎉

Tips for extra success

• Make multiple mops and rotate them daily: this way you always have fresh eggs available.
• You can also carefully remove the eggs from the mop and place them in an egg tumbler. This keeps the young ones separate and increases breeding success.
• Dark yarns make the eggs more visible.
• Place a sponge filter or air stone in the breeding tank to prevent mold on the eggs.
• Check the mop in the morning – that's when most eggs are laid.
• Feed the parents live or frozen food (e.g. artemia, daphnia) for healthy, fertile fish.

Common mistakes

• Using cotton: it rots in water, so always use acrylic.
• Don't rinse the mop: this will cause lint to build up in your bin. A quick rinse will fix that.
• Leaving eggs in the main litter box: they're guaranteed to disappear. Remove the mop from the litter box in time.
• No aeration: Without airflow, eggs quickly mold. A simple air stone works wonders.

Conclusion

Whether you want to breed danios, rice fish, or similar small egg-laying fish, a breeding mop is the easiest and most reliable method. You can make one yourself in just fifteen minutes, and the reward is a tank full of happily swimming fry. 🐣✨