Written by Dan
The first time I saw what at the time I thought was a bug crawling around on one of my live rock, I thought “Wooo that bug is crawling around under water!” I thought it had crawled into my tank. I didn’t know it was actually a Pod.
What this article covers
- What are Pods?
- Are Pods safe for my aquarium?
- Do pods help my aquarium?
- What is the difference between a copepod and an amphipod?
- What do copepods and amphipods eat?
- What eats copepods and amphipods?
- Buying Copepods and Amphipods
- How do you acclimate copepods and amphipods to your aquarium?
- How many pods should I have in my tank?
- Conclusion
What are Pods?
Copepods and Amphipods are actually crustaceans. Yep they are in the same grouping of animals as crabs, lobster, and shrimp. They are just much much smaller. Think about it, if you saw a crab or shrimp the size of a fly it would look like a bug. Many copepods are actually too small to be seen by the naked eye, especially in their juvenile size.
There are actually around 13,000 different types of copepods and slightly under 10,000 types of amphipods. These creatures in one of their many forms can be found in almost any watery habitat from the ocean to lakes, rivers, and even damp leafy forest floors.
Do pods help my aquarium?
Pods are very helpful for you aquarium. First and foremost they provide a good source of nutrition for many of the other critters running around your tank. Lots of larger invertebrates are either omnivore or straight up carnivores. They will actively hunt down pods for dinner.
What is the difference between a copepod and an amphipod?
The biggest difference between copepods and amphipods is their size. If you have actually watched it crawl across a rock or the glass of your aquarium, 9 out of 10 times you saw an amphipod. Amphipods range from 1mm to 340mm. In contrast copepods are generally between 1mm and 2mm large. Many copepods are actually planktonic for much if not all of their life and will just float around in the water invisible to the naked eye.
What do copepods and amphipods eat?
Their diet is the second biggest differentiator between copepods and amphipods next to their size. The smaller species will feed on microscopic algae in the water column. The larger copepods feed on algae growing on the rock and glass. Some of the larger copepods will also feed on their smaller cousins.
Amphipods primarily feed on detritus. They will scavenge the rocks and sand in search of dead organic material. This material can range from the bodies of dead tank mates to fecal matter. Yep that’s right, they are poo eaters and if your fish are as full of poo as mine this is a good addition to your cleanup crew.
What eats copepods and amphipods?
Lots of things will eat your pods. They are one of the lowest members on the aquatic food chain, just above algae. Many of the larger species of pods will eat the smaller species. Larger invertebrates such as crabs and shrimp will also eat on pods.
Many fish love to eat these guys as well. The Madorin fish for example are known to be finicky eaters who will often only feed on pods. Without an active population of pods to hunt down and eat, your Mandorin fish will likely wither away and die.
Buying Copepodas and Amphipods
With the need of these critters to sustain popular aquarium fish like the Mandorin it is quite possible you may find yourself not being able to sustain a population of them through natural reproduction. The good news is you are in luck. You can buy enough to keep your fish and inverts fat and happy.
There are many locations that sell bottles, bags, and jars of these little guys by the 100s and 1000s. The price will vary depending on the type of pod you get and the quantity.
I highly recommend as you add these to your tank that you buy a variety of them to help keep a diverse ecology. Try to switch up what kind of pods you buy and from what companies to help promote this diversity.
Setting up a refugium to grow an algae like chaetomorpha encourages this algae to grow in an unseen location in your stand and not in your display tank. You simply let it grow and cut back the growth every so often removing the cuttings from the tank. This helps ensure you are actually taking out the nutrients that feed the algae not just transferring it from one form to another until, well until the conditions are just right for a terrible algae bloom.
How do you acclimate copepods and amphipods to your aquarium?
As with any invertebrate it is best to drip acclimate them. That said because these are primarily food I simply float the container for a half hour or so to get the temperature to match the tanks.
I will then try to push them out of the container close to the rockwork and any caves or crevices I can reach. By doing this it gives them a better chance of getting into the rock where a larger number of them will have a chance to breed and multiply.
Conclusion
Ultimately having copepods and amphipods in your tank will make it more diverse. The more diverse you can make your tank the better it will do in the long run. We are trying to recreate our own little piece of the ocean in our tanks. The ocean is vast and has all sorts of creatures from the microscopic ones to those bigger than your house. Helping to build a thriving colony of little creatures will inevitably help the bigger more eye catching ones.
What is your experience with Pods? Let us know in the comments below.