Got Grindal Worms?

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Some betta keepers believe variety is the spice of life when it comes to the food they feed. So you will find they serve up various things on the dinner plate. Often presented in the rotation will be their favorite pellets, frozen bloodworms, adult brine shrimp, mosquito larvae in season and grindal worms. Some include a bit of frozen pea in the routine as well just to keep things regular.

Grindal worms are relatively easy to culture since they thrive at room temp.

And I have to confess. Whenever I hear the term “Grindal worms” I think of some character from the Hobbit. Just sounds like a name that should be from that movie, don’t ask me why.

Anyway Grindal worms make great betta grub. They are easy to grow, very nutritious, and don’t harbor any pests. Size-wise they weigh in at about half the size of white worms. Just beware that feeding them might unleash a feeding frenzy in your fry or sorority tank some bettas get so excited over them.

To help with that here are three videos which will show you two ways to cultivate them. There is no one best way to do this. Using a method that works and produces lots of worms is what counts.

This first video covers how to set up your Grindal (or white worm) cultures. The process for raising both is about the same. To make this happen you need

  • a hand drill with 1/16″ bit
  • a couple of those small disposable plastic storage containers,
  • media to grow them in,
  • bottled water,
  • scraper of some sorts,
  • starter culture.

The home for your Grindals are those Ziploc disposable plastic tubs readily available at the grocery store. (White worms would require something about twice as big.) You want to drill air holes into those along the sides.

Then add some potting soil. (Others use peat moss, or coconut fiber or reptile bedding made from coir (ground coconut husks which holds moisture well and has a neutral pH.) or pot scrubbies if you care to go soil less. (More on soil less in a bit.) You want something that doesn’t tend to dry out on you. (Peat moss does do that.) When using potting mix put in maybe an inch’s worth into your container. Close counts. With the soil be sure to break up any lumps.

To this add enough water to make it wet. Not sopping but wet. Just don’t overdo it because you can always add more water. Mix well.

Then add your starter culture. In this case white worms. For more on Grindals you have to go to video #2.

There’s a few good points to take away from this one.

To start off don’t miss the no charge fry feeding tip. That would be when betta fry have outgrown baby brine shrimp, it’s Grindal worm time!

Then you get an eyeful of a thriving culture. Worms galore. Crawling up the sides and everything.

You pretty much do the same to start the new Grindal worm culture as with the white worms. Gouge a square of worms out of the existing culture, stick it in the new culture and that’s it. Note there is no spreading them around or anything.

IMPORTANT: The choice of Grindal grub used is a salmon and potato based dog food. Spritz the kibble with a bit of water to soften it up. This choice of food is a great idea. It loads them up with all sorts of good nutrients. While I don’t know for sure which brand of dog food was used, here’s some choices. Following this suggestion will fatten your Grindals up and top them off with vitamins and Omega 3.

Please don’t overlook the choice of food here. Some suggest cat kibble or line of a powdered baby food among other things. Whatever you use you want to feed your worms well. Because whatever you’ll be gut loading them with is what your fish in turn will get when they ingest the worms.

Harvesting Grindals Made Easy

Now the trick of course is to harvest your worms cleanly. These videos didn’t get into that. So here’s the trick to pull that off. You’ll need:

  • small piece of plastic
  • spray bottle with dechlorinated water
  • collection container like a plastic shoe box

Lay a piece of plexi glass on top of the culture. Or the top of a CD case. The worms will naturally crawl on it and congregate.

Come harvest time just pick up the plastic, grab your spray bottle, and spray it while holding it over the plastic shoe box. (BTW, a quick search on Google will show you what these look like if you don’t know. Anything similar will do. Should be $5-$7. Doesn’t even have to be that big. But being bigger gives more landing pad for your worms.)

The water will run off the plexi-glass into your container of choice as you spray away. It may take a bit of practice but it works pretty slick once you get the hang of it. Then just put the now cleaned off the plastic whatever back on top of your culture and you’re good to go for next time.

Now you can either suck the harvest up with a baster directly, or if the water is a bit dirty, dump everything into a good sized clear plastic cup, and fill it up with water. In less than a minute the worms will settle to the bottom so you can pour off most of the water to get rid of the suspended dirt but leave the worms behind. A second rinse will usually be enough to clean up your worms good enough for feeding. Any dirt won’t hurt anything really. So don’t obsess over it.

Bath time over you simply need to turkey baster the worms up and squirt them into your tanks into the waiting mouths of your betta fish.

And if this approach to harvesting isn’t to your liking here’s another.

Soil-free Grindals

Just for those who prefer growing soil less here’s a quick vid on how you might do that.

Here’s the highlights of this one:

  • The approach used for letting the air in here involves putting decent sized holes in the lid and filling each with polyfiber. I’ve also seen say a half inch by three inch hole cut in the top and that covered with either a scubbie like these or a coffee filter is taped over it. That way you let the air in and keep the worms in, while keeping any potential pests out too.
  • The grow media is several stacked pot scrubbies. Get the cheapest ones you can find. As suggested earlier the worms are covered with a bit of plastic for ease of harvesting.
  • You want to see a bit of water in the bottom. That tells you things are moist enough. Just dump that water out and spritz the scrubbies to replace it at least once a week.
  • If you need a piece of plastic a good source would be a milk or bottled water jug, or say a juice bottle.
  • Room temp 70-75F 21-25C is good. If your house is colder you might put them on top of the refrig or someplace else that’s a bit warmer. Just keep it darker. Direct sunlight is out as the worms don’t like it.

I’d say this approach can be ramped up way more than what is shown in the video. You might also want to cut the harvesting plastic to be just a tad smaller than the scubbie. That way you cover the entire grow area making harvest easier.

Four Parting Tips

  • It’s always a good idea to have a couple of cultures going at the same time in case one for whatever reason goes bad on your unexpectedly.
  • Once established you should expect a culture to keep going strong for as long as six months. All you need to do is keep replenishing their food and they’ll be happy campers. Just don’t over feed. If food lingers too long mold will take hold. Not a disaster. Just pick it off. But if you can avoid it, do.
  • Spritz as needed to keep the culture moist. If you over do it the worms will climb and cling to the sides. Just leave the lid off to dry things out some.
  • If you go soil less you’ll want to use three to five scrub pads.

So there you go. Whether you go with the first method or prefer going soil-less, you are now ready to join the ranks of Grindal worm wranglers!

And if you’ve never seen fish inhaling Grindals well here you go. This is a pretty nifty feeder actually. Just not sure what it is. But it allows the Grindals to slowly “escape” into the water a few at a time. Which of course will be the last time they escape anywhere but then that’s what you are raising them for.

About Lucas
Putting a name with a face I'm Lucas Smatana. Like you I'm passionate about betta fish and hope to share my enthusiasm. The idea here is to make sure you get helpful info and useful ideas on betta fish care that really work. To insure your betta keeping experience is a good one both for you and your fish. So that you and your pet enjoy a long, happy and healthy relationship.

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