Anyone who keeps a saltwater fish tank or reef aquarium will probably notice what appear to be tiny white mites swimming around in the tank water at some time or another.
But what are these creatures? How did they get into your tank? And, are these water fleas bad for your aquarium?
Keep reading to find out!
What Are These Tiny White Things In My Fish Tank?
First of all, don’t panic!
These minute creatures are actually harmless crustaceans, rather like super-tiny shrimp. During adulthood, these critters live deep in the substrate where they remain unnoticed. However, during their larval stage and as juveniles, the sea mites, as they are also sometimes called, are free-swimming, and that’s when aquarium owners notice them.
Common Worm Species
You might also find a few of the bugs stuck to the glass viewing panes on your tank. Don’t confuse the “pods” with Planaria worms that you might also see crawling up the glass. These tiny buff-colored or white worms can find their way into your tank on plants or on new fish. Mostly, they live unseen in the substrate, venturing out at night to feed.
Again, Planaria are just about the most common type of worms that you find in your fish tank. The worms are harmless to your fish, but they can be a sign that your water quality and general tank cleanliness need attention.
How Did Amphipods And Copepods Get In My Tank?
Amphipods and copepods usually find their way into your fish tank as hitchhikers in live rock, sand, and aquarium plants, depending on the species of critter you’re dealing with.
Mostly, these harmless residents remain invisible to the naked eye. However, when the water temperature is warmer and there’s plenty of food available, you might see a bloom of these “pods.”
Copepods are found in all aquatic ecosystems, including brackish, marine, and freshwater, whereas amphipods occur primarily in saltwater, although there are a few terrestrial and freshwater species, too.
What Are Copepods and Amphipods?
There are thousands of species of copepods and amphipods that make up the plankton soup that’s commonly referred to as zooplankton. These creatures live on phytoplankton, which are microscopic algae and plants that drift through the water column, microzooplankton, and detritus.
Are “Pods” Dangerous To Fish?
Of the thousands of species of “pods” that exist, only a few are parasitic or carnivorous, and those are very rarely encountered in marine or reef aquarium systems.
In fact, many marine species feed on amphipods and copepods as their primary food source, and some hobbyists breed these creatures in a refugium specifically for use as live food for fish for adult fish and homebred fry.
Another creature that you might encounter in your aquarium is the isopod. Isopods are also commonly called fish lice, pillbugs, and roly-polies, and they occur in all marine habitats. There are many species of isopods, most of which are completely harmless, eating algae and general detritus.
However, a few isopods are parasitic or predatory and can present a danger to some reef animals.
How Can I Get Rid Of Water Mites?
Most aquarists are more than happy to see a thriving population of free-living copepods and amphipods in their tank as the creatures provide a food source for fish.
These “mites” are part of a healthy marine ecosystem, and they are also a crucial food source for many aquatic species. So, getting rid of these tiny visitors isn’t deemed to be necessary by many hobbyists.
However, if you have any concerns, there’s a long list of natural predators that would gladly help keep the “pod” population under control for you.
All the species that I’ve listed below relish sifting through the sand or picking at the live rock to grab one of these tasty little snacks. I would point out that many of these species are not suitable fish for beginners, as they can be challenging to keep in the home tank, and they need a stable, high population of “pods” to sustain them.
- Mandarin Fish
- Sand-Sifting Gobies
Also, many species of soft corals and small polyp stony corals feed on plankton and plankton byproducts.
As mentioned above, all these creatures need a fairly heavy population of bugs to survive. You can supplement your tank’s supply of home-grown supplies of “pods” by buying some for use as fish food from a specialist supplier and raising them in a refugium or other micro-culture system. Then you can simply harvest the bugs and feed them to your fish.
Many marine stores and online aquarium product suppliers sell live food colonies.
Alternative Methods Of Removal
If you don’t have bug-eating creatures living in your aquarium, a population of “pods” can be a nuisance.
Often, when dense numbers of these water mites are present in our tank in their free-swimming life stages, they can irritate your fish by crawling on the fishes’ skin. You might see your fish flashing against objects in the tank or shaking in response to the irritation that the bugs can cause. That can be extremely tiring and stressful for the fish, potentially leading to severe health problems.
In that case, you’ll want to protect your fish by getting rid of the bugs. The best way to do that is to use a HOB style canister filter with a very fine pleat cartridge or fine micron sleeve installed that will filter the mites out of the water pretty quickly.
Out Of Sight And Out Of Mind
Remember that once the free-swimming bugs reach adulthood, they will disappear into the substrate and crevices in your live rocks, where they will remain hidden and harmless. Many fish and inverts will enjoy snacking on any “pods” that they find, so you might prefer to let nature take its course and leave the bugs undisturbed.
I hope you found our guide to those tiny white bugs that you sometimes see in your marine tank helpful. If you did, please remember to share.
Generally, copepods and amphipods are not harmful to aquarium residents, actually providing a valuable food source to many species of marine fish. However, these tiny creatures can be an unwelcome irritant to your livestock, in which case you can remove them easily simply by filtering the “pods” out of the water.
Did you have a population of free-swimming water mites in your tank? Did you get rid of them or allow them to stay? Tell us in the comments box below.