No mess, no fuss, no missing ventrals...at least I've not heard of a theory linking Vinegar Eels (VE) with missing ventrals ;)
But how does one go about keeping, raising, and dividing VE cultures?
Well, I'm glad you asked ;)
VE are actually Turbatrix aceti, a nematode. They grow only to 2-3mm in length and take absolutely nothing other than apple vinegar and some water to keep them happy and reproducing like the Dickens!
Where to get them? Most pet shops or local aquatic shops either carry a starter culture or can get them in for you for $10-$20, but the best place to get them is off one of your fellow fish keepers, particularly if you belong to a society, because chances are, you'll get them for nix (see, there are lots of great reasons to join your local society).
When you receive your starter culture, it will likely be in a bag. To successfully raise them, you need to transfer the contents into two transparent wide-mouth containers. These can be anything from soda bottles with the top cut off, to a couple of these:
Maison Jars (pickling jars)
These come in a range of sizes, and the bigger you go, the more VE you'll be able to culture in a single culture, which, if you intend on breeding large numbers of fry, may be a good thing.
So, you have your containers (I have a culture growing in a glass coffee jar even), and you have your donated started culture (because I now you all went out and joined a local society). Pour half your starter culture into each of your containers.
Many people have their suggested ratios of apple vinegar to water. I like mostly vinegar, so about 80% apple vinegar to 20% aged water is what I use in a 500ml culture (that's 400ml apple vinegar to 100ml aged water for those not wanting to get a calculator out ;)).
Many people also suggest adding sugar or slices of apple to their culture. Sugar apparently makes the culture take off, but it may also reduce the life of the culture. Slices of apple can cloud the water (from experience). Neither are really required so I'd just leave it well alone.
So - back to the starter culture - you've poured in your starter culture into two containers. Now add your 20% aged water, and then add your apple vinegar. This is the stuff I use:
The main point here is to use an apple vinegar with no added colours, flavours or preservatives. It's also why I only use aged treated water. This is going to end up in your fry - make it worth the effort.
So now you have two containers with your cultures sitting happily within them. They do smell a little bit like spilled vinegar, which may attract unwanted bugs or pets to them. After all your hard work, we need to stop them from being contaminated.
Get a chux cloth - a new, clean one...one that has never been used (get the picture). Cut a square of it off. Make sure it is big enough to cover the top of your container. You can keep it attached with a rubber band. If you went that bit further and purchased the maison jars, you can slip out the central lid insert, which will leave you a threaded ring. You can then screw that down over the chux to hold it in place...like this:
Completed VE Culture waiting to be gobbled up by well loved fry
Your culture should be stored somewhere safe and preferably somewhere out of direct sunlight. Inside a utility cupboard your spawn tank is sitting on would be handy. This will cut out the light, and cut out any traces of vinegar...at least I don't seem to smell it anymore and my cat doesn't seem to sniff around the cupboard either.
It should last at least 3 months before it crashes, or so I'm told. I've never had one crash to this point with my oldest culture being 4 months old at the writing of this post.
You require a wide-mouth container as the VE want to get to the surface to breath. They will pack themselves in at the surface, regularly circulating so everyone gets their chance to gasp. If you shine a torch through the back of the culture, you'll see millions of glittering VE writhing around in there.
This is also why a narrow neck bottle is the perfect way to harvest them:
see previous post.
Unlike other micro-food for fry, VE doesn't die in the tank and end up as gunk on the bottom. VE will happily survive in the water column until they are eaten. They don't grow to massive proportions while living in your tank - 2-3mm is it. Granted, they don't quite have the same nutritional value as microworms (MW) and they have nowhere near the benefits of freshly hatched Baby Brine Shrimp (BBS), but for the first few days after hatching, your Betta fry live off their egg yolks. When they begin free swimming, they are extremely small and feed of infusoria and other microscopic creatures living in your tank. Adding VE to the diet gives them something else to chase and devour, giving them excellent exercise and keeping the tank clean. By the end of the first week, they can then be switched to BBS. If you still have some small fry, it will do no harm to add a little VE to the tank.
But why two jars? If you have an accident, or a culture crashes, and you have hungry fry to feed, you better have a plan B!
Check your cultures once a month and divide if it looks like you have a massive amount of VE congregating at the top - it will look like a cloud of them suspended in the fluid. Rinse and repeat - and give some to your next new comer to the society meet...never hurts to pay things forward ;)
Good luck with your spawns!
