Microworm Versus Vinegar Eels (One Man's Perspective)

I don’t have a lot of nutritional facts to go on, but this isn’t through a lack of research, ongoing research at that. If more information comes to light, I’ll add or retract comments as required.

First and foremost, microworms and vinegar eels are both nematodes, or a type of round worm. One lives in apple vinegar, the other can be raised on a number of different substances.

Microworms fall through the water column when added to the fry tank and rest on the bottom. They die within hours and will commence to foul the water. Unless cleaned before addition, the medium will also cloud, and possibly foul, your water.

Vinegar eels will survive for days in the fry tank, swimming at all levels of the water column. It is unlikely to be found dead on the bottom and therefore, is unlikely to foul the water. If not harvested correctly, medium can raise the acidity of the fry water.

If fry are overfed with either nematode, it will foul the water.

Fry tanks build up gunk on the bottom. This comes from the waste of the fry, the waste of the parents before removal, uneaten food, plants, and general detritus. It is safe to say it is not the kind of thing you want your babies playing in if you can possibly help it. Indeed, there is a theory floating around that too much time spent in this muck can lead to a higher incidence of missing ventrals in fry.

In general, both MW and VE have a similar protein percentage of between 40-50% of the worm. Both also have around 20% fat content. I believe it is the carbohydrates that allow the microworm to claim a better nutritional value, but this is dependant on the medium the microworm is raised in. The higher the protein and carbohydrate level of the medium, the higher the level found in the microworm. Vinegar eels must be raised in apple vinegar, where the nematode lives off the bacteria, which causes the vinegar’s acidity (Mother Of Vinegar).VE has no carbohydrate value.

In comparison, BBS has a protein content of 60-65%, fat and carbohydrate levels of around 25%.

High levels of carbohydrates, fats, and especially protein is what will allow your fry to grow bigger, faster.

On nutritional scales alone, the microworm is slightly ahead of the vinegar eel, but not by much. The generalised statement often read on the net of VE being far inferior nutritionally to MW is false.

The fact the VE can survive in the water for much longer, and swims in different levels of the water column is a definite plus. As it also requires the fry to swim after it, I.e. actually hunt it, is another bonus. VE living in the water allows the fry to graze throughout the day, so feeding needs to be less regimented and less often.

Both VE and MW are behind BBS nutritionally, but BBS only survive in the tank for a few hours due to reduced/nil salinity, but then, you should only be feeding freshly hatched BBS which still retain their egg sac, giving them even higher levels of protein and fats (less than an eight hour window).

Monitor the feeding of your fry to ensure you don’t overfeed regardless of your choice of nematode. Cleaning up after each feed session may also reduce the chances of ventral-less (hands free) fry.

So there's the run down as far as I know it. My choice is to use VE. I'm still trying to learn how to hatch BBS...but that's another story...