An Isopod is a type of crustacean that is most commonly located in shallow marine locations, and there are actually more than 5000 species of Isopods today. Some species of Isopod are even terrestrial, like woodlice.
They are one of the most morphologically diverse of all the crustacean groups, coming in many different shapes and sizes and ranging from micrometers to a half meter in length.
More often than not, Isopods do not look alike, but they do have some commonly found features. All Isopods will have two pairs of antennae, compound eyes, and four sets of jaws. The body of an Isopod is made up of seven different segments, and each of these has its own pair of walking legs.
Isopods also have a short abdominal section that is made up of size segments, which are called pleons, and one or more of these segments is fused into a tail section. Each pleon will have a set of limbs that are called pleopods, and these are used for both swimming and respiration.
Around half of the known Isopods live in the ocean, and some are large and spiny and living in the sea, whereas others are smaller parasites that live on fish. There are also others that live in coastal and shelf waters, and they move around the seafloor or live on plants.
The Isopods that do live in the oceans can do so by using their pleopods to breathe through a gas exchange. Those that live on land have been able to develop their pleopods to include pseudotrachea, which function as gas exchange organs and do not need to be fully submerged in the water.
Lots of species of Isopods are actually beneficial to reef tanks, feeding on dead or decaying matter, but there are some species that are parasitic or predatory. They are commonly found in reef tanks, and they will move around when it gets dark.
Munnidae - (Common Name: Munnid Isopod, Isopod, Pod)
The munnid isopod is a harmless and beneficial herbivorous isopod, and these are pods that measure at around 1 to 2 mm in length, and they can typically be found on the glass and rock surfaces in the tank.
They can typically be found on any surface that has algae on it. More often than not, you will be able to see them congregating in a specific area in order to eat the algae that you either can or cannot see. The waterline is one of the best places to observe them looking for food.
When it comes to telling the difference between male and female Munnid Isopods, you can look out for certain traits. There are some variations that you will notice, like how males can be seen with powerful front appendages, and females can be seen carrying eggs at times.
Male appendages are the main way to differentiate from a female, and these can be found on their front, and they look almost claw-like. Males can also often be seen fighting over the female.