Culturing Freshwater Amphipods for Live Food

Many fishkeepers swear by feeding their pets live foods. Some popular ones you’ve probably heard of are baby brine shrimp, microworms, black worms, vinegar eels, etc… One you may not have heard of (other than complaints of infestation) is the lowly amphipod or “scud” as they are sometimes called. Saltwater enthusiasts have been using amphipods as fish food for some time now, but there are freshwater species that we can take advantage of for our pets. If you aren’t familiar with freshwater amphipods, check out my Amphipod Species Profile.

It is fairly easy to start and maintain a colony of amphipods for use as live food. I keep them in my aquariums as a sort of naturally occurring snack, but you can keep them in their own container to harvest as needed.

Equipment List

  1. a vessel at least 1 gallon in volume (obviously the bigger the container the greater the possible yield)
  2. dechlorinated freshwater
  3. something for the amphipods to cling to (like plants or a filter sponge)
  4. food (plant clippings, fish flakes, vegetable ends, etc…)
  5. airstone or other gentle filtration (optional, they do breathe with gills, so more oxygen means greater survival rates)
  6. a sample of amphipods to begin your colony with

Getting Set Up

First thing’s first. Choosing an appropriate vessel to store your colony. I suggest a minimum size of 1 gallon, because while a colony can be kept in smaller containers, this will reduce the total size of the population. If you want to keep a stable colony you can harvest from regularly, the bigger the vessel the better.

Something like a 1 gallon milk jug will work. Just make sure to rinse it out thoroughly before using it, but do not use soap if you can. Any soap residue left behind could harm the amphipods. If you do use soap, make sure to rinse it very thoroughly. Something like a 2 or 5 gallon bucket is even better. You can pick them up from a hardware store inexpensively. They have handles and are easy to move around. The best is if you have an old aquarium that you aren’t using. This way you can observe your colony from all angles and appreciate their cute habit of swimming around.

Once you have found a suitable container, next you will need a good location to store it. You want somewhere that will not have major swings in temperature. If you can keep it under your tank in a cabinet, that is perfect. If you have a semi-finished basement that works too. If you are using something like a bucket to store them in, it’s probably best to keep it somewhere out of sight. Otherwise your spouse/mother/roommate may be giving you “the look.”

Once you’ve found a container and a good spot to keep it, add your dechlorinated water and your plant or filter sponge. If you’re going to be using some filtration, set that up now as well as an airstone if you are using one. If you are using a filter, I would suggest a sponge filter. If you are going with a HOB or some other power filter you’ll want to put a sponge or some fine mesh over the intake. Otherwise your scuds will get sucked up and either killed or they’ll set up shop in the filter media. That may not be so bad, but it’ll be tricky to harvest them later. So take my advice and go with the sponge filter.

Amphipods are very hardy, and in my experience are not bothered much by low levels of ammonia and nitrite so you can add your starting culture right away without having to cycle the filter. If you have patience (bless you) you might as well wait a bit to allow for the filter to cycle, because why not? If you aren’t familiar with what “cycling” means, check out my article on the Nitrogen Cycle.

If, like me, you can’t wait to throw it all together, I have experimented with keeping dozens of scuds and some food in a small breather bag held in a large cup. I observed them for 7 days and then released them back into their tank. In that time there were no amphipod deaths, and they remained active for the entire time they were in the bag. So it seems they can tolerate increased ammonia levels rather well.

Feeding Your Amphipod Colony

You can take some liberties with how often you feed them. I like to feed them maybe once every other day. As long as the food from their previous meal is completely gone, they will happily begin munching on the next meal. The more you feed them the faster they will reproduce. If your water starts to become foul, do a 50% water change.

To say scuds are not picky eaters is an understatement. I have yet to see them not dive right into any food I’ve exposed them to. I feed them fish food, dead plant material, powdered egg shell… I’ve seen them eat dead snails, fish, and even the dead of their own kind. Is there no decency among amphipods? The answer is “no.”

Colony Maintenance

Amphipods may be hardy creatures, but they aren’t immune to suffering from poor water quality. I recommend changing the water at the very least once a month. This is not only to remove unwanted pollutants, but this also reintroduces important vitamins and minerals that will be depleted from the water over time. Old tank water tends to go acidic over time. This can reduce the yield from your colony, so better to keep a regular water change schedule. Feel free to change the water more often. As long as it is treated properly, they can only benefit from it. The more often you change the water the better, as this will result in greater yields.

I suggest putting a nitrogen-soaking plant like hornwort in their container, and make sure the plant receives adequate light. The plant will help to keep the water healthy and will help oxygenate the water. The scuds will also appreciate the thin needles of the hornwort as a place to cling to as they rest.

Here is a closeup of a small colony of amphipods. This species grows to about 1/4 of an inch.

Harvesting Amphipods

Finally, the big pay off! There are a few different ways to harvest your scuds. Remember that filter sponge or plant you added at the beginning? Amphipods naturally cling to things like plants and rocks. It keeps them feeling secure. So if you are ready to harvest, quickly and smoothly pick up the filter sponge or plant and dip it into a smaller container of water. Many amphipods will still be clinging to the sponge when you pick it up, and they will fall off when you dip it into the new water. Be careful that you don’t lose any dripping onto the floor in the process. It’s good to keep your smaller container close to the bigger one when harvesting the scuds.

The second option, which I like to use, is to put their favorite food in the bottom of a small cup. Add a rock or something to weigh down the cup, and place the cup face-up at the bottom of their container. I let the cup remain for an hour or so and then quickly lift the cup out of the water, without spilling the contents. Usually there are many dozens of scuds inside the cup, eating the food. Most of them don’t even seem to notice they’ve been caught until they take the plunge into the platy tank.

A third, and in my opinion least effective, way is to use a brine shrimp net. Scuds can hustle when they want to, and may be difficult to catch. If you have a big enough colony and a big enough net, you might be lucky enough to scoop out a bunch of scuds that are swimming around in the open water.

Simply add them to your aquarium and watch your fish enjoy the chase!

Here is the cup I use to harvest scuds from my 3 gallon planted tank. I cover the top with a piece of cheesecloth to keep adult shrimp and snails from getting into the cup. The brownish lump is a piece of scoria to keep the cup at the bottom of the tank.

Where Do I Get Scuds in the First Place?

You have three options: find someone who is willing to give you some of theirs (this is the best), purchase some online (which is what I did), or catch them yourself from the wild (euu gross!). You might want to check my Store page. I sometimes have scud starter cultures available.

Catching Amphipods in the Wild

It’s not difficult to catch wild scuds. All you need is a net or some other scoop and a tolerance for getting muddy and possibly stinky. Depending on where you live, you may be able to find different species of scuds in different sizes. My brother and I used to catch rather large ones from a lake near our home. What we did was dig up big scoops of leaf litter and mud from the lake and pick through it by hand. We would get maybe a dozen or so from each clump. We would also find lots of snails and other creepy crawlies that many fish enjoy.

Amphipods cannot bite you, so there is nothing to fear from them directly, but of course, depending on where you live there could be parasites or other nasty bitey things in the sediment. So it may be a good option to simply drop a few bucks on a starter culture and avoid the hassle of getting in the mud. If all goes well you’ll have a steady supply of amphipods for as long as you keep them. So a little expense up front will seem like nothing after a several months or years of home grown food.

The culture may be slow to start, but keep at it and within a month or so you should start noticing your scuds have increased in number. Soon you’ll have more amphipods than you know what to do with.

Maybe give some to a friend!

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