Home Grown Food - Infusoria Edition

Let's say you have fish in your community tank, and they have been laying eggs, and usually, those eggs just get eaten by other fish. Or maybe those eggs hatch, but then nothing happens. The fry either get eaten or disappear into the filter system. You never really intended to breed fish, but now that they are doing it on their own, this seems interesting! Or maybe you set out to do this, but now are hunting for option for how to feed said baby fish.

Regardless of how you got here, many of the baby fish (or “fry”) you'll find yourself caring for are much too small to accept any kind of prepared food product. Don't fret, generally fry grow quickly, and you can easily culture food at home to be able to raise them to a point where they are capable of taking larger food morsels. So, on today's episode of Homegrown Food, we're here to talk about Tiny Food for Tiny Fry Edition I (I for Infusoria!).

Perhaps the easiest of all fish foods to culture at home, is something called Infusoria. This is a generic term that basically means microscopic organisms. It has fallen into disuse in the scientific community as it is too general of a term to be of much use in all but the most general settings. For fish keepers it continues to be used as a term that means a culture of microscopic organisms that are a suitable size and temperament for being eaten by the tiniest fry.

All these takes are a watertight container that allows for light to get into it, water, and something for the microscopic critters to eat. You want a container that is at least a quart, but not bigger than a gallon; canning jars, clear, circular cambros, and old ice cream pails all make good choices. Whatever you choose, make sure you can get a hand in it for harvesting your food, as well as cleaning it later. Fill this container with water, preferably, biologically active water, like water from a flower vase (without any additives), or the aquarium water from your most recent water change. Then add food, cover it with screen or a few layers of cheese cloth or something else that bugs can't get through, and leave the whole mix in the sun until the water gets cloudy, and then goes clear. The cloudy growth is bacteria and yeast, as the system clears, the balance of organisms will have shifted as the infusoria eat the bacteria.

In regard to food, Infusoria can eat just about any vegetable matter you can think of. Lettuce is a common choice, as are rice or potato mash, fish food, and banana peels (a great choice if you want to use the left-over liquid as an organic fertilizer for the garden). Wash any vegetables you feed into your culture, cook and mash any starchy vegetables, and if you choose to use a leafy green, give it a blanch, or quick dip in boiling water to help break down their tough cells. It doesn't hurt to use more than one food type. Many hobbyists use commercially prepared mixes to feed their infusoria, and these are fine to use and available from your Local LFS. It doesn't take much food to get this rolling, start with a few leaves of lettuce, or a cup or so of mash in your gallon. If/when your culture develops a scum on the surface, you should either mix this back in, or scoop it off with a spoon to ensure good air transfer to the system.

If you'd like to jump start your infusoria culture, squeeze out one of your aquarium filters into the culture. Some people like to add a tiny bit of commercial yeast mix and there isn't anything wrong with this. Avoid the temptation to grab some pond water from your local park. You don't know what's in there, both on a fertilizer level and an aquatic predator level. There are tons of tiny organisms that can get big enough and hungry enough to target your fry as food, and they are good at it. This is bad.

Then all that's left is feeding it to your baby fish! Use a siphon, and remove a couple drops of loaded water, and target feed your fry (gently baste the food in their general direction). Try to avoid sucking up decaying matter that you've been feeding to the infusoria soup. There's a lot of microscopic food in each dropper of food, so a little goes a long way here. The flip side of this is that the food is very small, and fry need a lot of it, so plan on feeding at least twice a day and three or four times daily would be better.

When your fry is big enough to take different foods, (which should take about a week) you'll likely still have quite a bit of infusoria soup left. Regardless of if your fry is big enough for the next stage of food or not, after a week or so, the culture will be spent; once it starts to go cloudy again, it's a sign that the bacteria are overwhelming the infusoria and it's time to move on from that culture. Remove whatever food product(s) that you were feeding it and pour the remaining liquid around any plants that might need a nutrient bump in your garden. They'll love it. We don't suggest using it on houseplants as unless you get 100% of the food out, it could start to decompose in the planter and thus smell, well, not great. It's also totally fine to pour down the drain or flush.

People who raise a lot of fish stagger their cultures of infusoria. The idea is to start more, smaller cultures on a schedule, so that those cultures are ready at different times, allowing them to feed more fish over longer periods of time. Stagger start times by four or so days. It wouldn't be a bad idea to do this, even for raising just one group of, this way, if your infusoria culture goes bad before you're done feeding the fry, your next culture should be in prime shape and ready to feed. If at any time, this starts to stink, it's time to move on from it and start anew.

There you have it! The easiest food to culture, for the hardest fish to feed! This system is tried and true, and with a small amount of tinkering, you'll have it down in no time. Avoid chlorine at all costs, and embrace the sunlight, and you'll have plenty of micro-organisms floating around in no time!