We have talked about the white bugs in our aquarium, but what are these brown “bugs” in my aquarium?
Every night at 9pm, the lights in our aquarium turn off. After about an hour of darkness, Andy and I peer into the tank with flashlights to see what comes out at night. One thing we have noticed were little brown “bugs” crawling on the rocks. After searching online forums, we found out these “bugs” are another type of pod, called Amphipods.
Amphipods, like Copepods, are tiny shrimp-like crustaceans, found in all seas, both in freshwater and saltwater. They are much larger than the Copepods we have seen in our tank, and brown in color. They are poor swimmers, which explains why we see them on the rocks instead of swimming around. They eat plant and animal debris and are a part of the healthy ecosystem of a marine tank. If we had a Wrasse, Mandarin fish or a Goby, they would be in heaven with this natural food supply!
If you plan on keeping a fish in your tank that needs amphipods, having this natural food supply is helpful, but may not be sustainable long term. Amphipods can be purchased for these fish, but can be expensive. Another option is buy amphipod eggs and hatch your own. Once these eggs hatch they can be put in your refugium where they will be filtered into your main tank and be a great food supply for your fish.