# Live fish food - Grindal worms



## mysiak (Jan 17, 2018)

I'm not sure if this is the right forum section for this topic, but couldn't find anything related to fish food (or Grindal worms except the for sale topics)..so here it goes 

I have been debating with myself for a long time about raising live food for my fish (livebearers). It can't smell, must need minimum of equipment and space and minimum care is welcome too. For some time I used to hatch artemia eggs, but despite having "low maintenance" hatching disc gadget it was still too much work with not enough of food produced. If I skipped just one disinfection of all the equipment, there were hardly any artemia hatched. Attempts with Moina macrocopa and Daphnia were total failures (too small jars and probably lack of appropriate food for them).

Then I moved to frozen cyclops, which are probably OK in terms of nutrients, but I noticed that fish were just a bit better looking and more "happy" with live food. After a long research about different types of live food I've chosen Grindal worms. I'm sure that most of you already know about Grindal worms and probably also breed them, but I'm new to the "worms world" 

I received the starter culture (synthetic method, yellow sponge) few days ago - don't be alarmed by green color, it's just spirulina powder. For some reason I find synthetic method less appealing, so I immediately started also "natural" containers with coco peat (coir, Lignocel). Plastic mesh is used to minimize peat sticking to the glass cover. I tried to glue silicone suction cups to the glass, just to realize that cyanoacrylate can't bond with silicone (they hold fine by suction though).. Well, lesson learned 

As for the food, at least in Slovakia and Czech Republic it's very common to use "sponge biscuits" (https://image.shutterstock.com/z/st...-isolated-on-a-white-background-415774450.jpg). However in my case they spoil very quickly, they smell bad in less than 24 hours. I switched to oatmeal flakes (the second most used food) and these seem to be much better. For good air exchange I cut small holes in lids and covered them with cosmetic cotton pads. They allow air in and out, but should keep pests away.

All three food boxes are still starting, there isn't enough worms for fish, but it should change in about a week or two.

If you have any recommendations or personal experience (good or bad), please share it


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## sbalabani84 (Oct 28, 2018)

Hi , I feed them dry cat food pellets. One or two depending on the size.of the colony.


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## mysiak (Jan 17, 2018)

jatcar95 said:


> I want to try raising some live food for my betta, I have some brine shrimp eggs on the way. I hadn't heard of grindal worms before though and it sounds as if they may be a good option as well. @mysiak, how did you go about starting (specifically obtaining) a culture of them?


Grindal worms are usually sold as a "starter culture" - a small box with a piece of media with worms in it. If you're lucky and don't live too far away from the seller, you can obtain a fully grown media as well. I'm not sure in which country you live, so can't really advise about the best source for you. eBay or some other fish breeder would be your best bet. Once you get the starter culture, you will need to inoculate your own breeding media (basically meaning adding a few worms in each box ). First few weeks will need a very sparing feeding, but once the colony establishes, they will eat about 1 tea spoon of food per "medium" box every day (obviously depending on the size of the box).

Currently I'm running 5 boxes - 1 with "artificial" sponge media and 4x natural coco-peat. Coco-peat provides the best results for me, but I still keep the sponge as a "backup". In case that something happens to one of the boxes, I can re-start the culture from this one.

I experimented with different foods for worms for a while, but ordinary ground oatmeal flakes are the best - they don't spoil so quickly and worms eat them without issues. And even if they get to the fish tank with worms, it shouldn't present any issue as they are often a part of staple fish food anyway.


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## mistergreen (Mar 3, 2007)

Foods with preservatives in them are better for me like cat food or store bread. Natural foods spoil/mold too fast in my environment. I sometimes add supplemental nutrients to the foods like protein powder, nutritional yeast, and a little spirulina.

I lost my grindal worm culture but my white worm is still going. White worms are larger version of grindals and they live in 55F-70F. They stop breeding above 70F. Grindals do better in temperatures above 65F.


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## mysiak (Jan 17, 2018)

mistergreen said:


> Foods with preservatives in them are better for me like cat food or store bread. Natural foods spoil/mold too fast in my environment. I sometimes add supplemental nutrients to the foods like protein powder, nutritional yeast, and a little spirulina.
> 
> I lost my grindal worm culture but my white worm is still going. White worms are larger version of grindals and they live in 55F-70F. They stop breeding above 70F. Grindals do better in temperatures above 65F.


Thanks for sharing your experience. I am using glass cover over the culture media - worms stick to it and it's very easy feed them to fish this way. I'm not sure that I could spread cat food under the glass evenly and in such a thin layer as with ground oat meal flakes. I will try giving them some old dry bread crumbs though, sounds like it might work. We don't have cats and wife would get a bit suspicious if I brought a bag of cat food home.  Btw. oatmeal flakes are perfect if worms eat them in less than 2-3 days. So unless I overdo it, they don't mold or go sour. Soy flour, spirulina powder and sponge biscuits went bad in just 1 day, so I don't use them anymore, even if other breeders swear by them.

I have the breeding boxes in the cabinet right above the tank, minimum temperature is about 22C (~71F) in winter and reaching 28C (~82F) during summer - that's with two fans cooling the tank and cabinet. From what I read, that's just too much for white worms, but ideal for Grindal.


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## mysiak (Jan 17, 2018)

I noticed that when I'm harvesting worms from the glass cover, there are fully grown Grindal worms and a lot of tiny worms, which I initially thought are baby Grindals. I stumbled upon information that these are in fact "micro worms" (the free-living nematode Panagrellus), which are being said to often occupy Grindal cultures and sometimes even over running them. Recently I've been harvesting maybe 5-10x more of these "micro worms" than Grindal worms. No idea where they came from and my fish fry seem to prefer them, so I don't really complain. However for my bigger fish I'd like to keep "pure" Grindal cultures. Any idea how could I promote growth of Grindal worms and suppress the micro worms living with them? 

Just thinking about it, I should first confirm that they indeed are not Grindal worm babies, so I'm going to separate a bunch of them into a separate container and see if they'll grow in size or just in numbers. Not sure that I can do any other "investigation" without a microscope.


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## mistergreen (Mar 3, 2007)

Yup, my worm culture crashed once and the micro worms crawled out of the substrate. I cultured them in mash potatoes. If you need free micro worms, they’re there in the substrate of your grindals.


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## Gerald (Mar 24, 2008)

You might be able to tell them apart by the way they move. Grindals are Annelid worms (segmented) and move mainly by extending and contracting their body, like earthworms. Microworms are Nematodes (non-segmented) and move by sinuous bending, like eels. Note: Annelids can also move by sinuous bending when they're in a hurry to get away from something. But nematodes can never extend and contract, as far as I know.


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## mysiak (Jan 17, 2018)

That's very interesting @mistergreen and @Gerald. I wasn't aware of these facts. They definitely move like snakes/eels, so I suppose that they are indeed microworms. And they're a little "stinky", unlike Grindal worms which practically have no distinctive smell 

In some of my boxes they pushed Grindal worms to the sides and microworms occupy almost whole surface area.

In other boxes they co-exist side by side, similarly to the attached picture.

Any idea how could I increase numbers of Grindal worms and suppress microworms? I don't want to wipe them, just have at least 1:1 ratio.

Btw. I'm feeding them with crushed oatmeal flakes, usually amount which they consume within 1 day. Occasionally I inadvertently overfeed them and have to remove spoiled flakes after 3 days or so. Not sure if this overfeeding could be causing increased number of microworms. Today I started another culture with as "clean" Grindal worms as I could obtain, but I'm sure that some of microworms got into the substrate (pure coco peat), so not sure that it will make any difference.


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## mistergreen (Mar 3, 2007)

You can start on a new bedding/substrate to control microworm population. They feed on microscopic life in the substrate. You'll find them in garden compost too. If your substrate 'smells' it's time for new bedding anyway.

Your culture looks too wet as well. That might be a reason for the imbalance of grindals to microworms.


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## mysiak (Jan 17, 2018)

Thank you for the suggestions, I am going to try keeping the substrate less damp.


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## mistergreen (Mar 3, 2007)

You can tilt you containers on an angle to let the excess water drain down.


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## mysiak (Jan 17, 2018)

mistergreen said:


> You can tilt you containers on an angle to let the excess water drain down.


In the "worst" boxes I added a thin layer of fresh dry coco peat over the top to absorb the extra water and it seems that it worked. There is no water to drain, even if I push on the substrate, no water comes out of it. Glass cover is not wet anymore and I think that I see more Grindal worms on the glass again. I believe that at this point I have ideal moisture level, now just to keep it stable long enough to confirm the impact of substrate moisture on cultures and ratio of Grindal and "microworms" (whatever they are).

If the size of worms really depends on the substrate dampness, I will keep a box or two too wet to have "microworms" and the rest of them favoring full sized Grindal worms.

Interesting animals, these worms..  I just wish I had a microscope.


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## mistergreen (Mar 3, 2007)

It would be fun to scientifically find the optimal moisture percentage. They make soil moisture sensors.


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## aquabillpers (Apr 13, 2006)

Microworms and Grindals? A bonus live food!

In my outdoor daphnia tubs I get a bonus of mosquito larvae and an occassional bloodworm.

(No sermons on the ML, please. <g>)

Bill


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