Reef Pests and Their Ramifications (Part 3)

This third part in a series of nuisance pests that can invade our marine aquariums while altering its symbiotic chemistry as well. Copopods are found everywhere that water is found and their are roughly about 12,000 known species of copopods hailing mainly from the sea. These crustaceans represent the largest source of protein in the food chain of life in the sea. Amphipods, or the small white swimming or crawling bugs in your aquarium also offer beneficial salutations to your tank and its inhabitants. These are not I will be focusing on in this article as these are beneficial food stuff for one. Nor will I be centralizing this article on decapods, which are the ten footed crustaceans with the first three pairs of appendages known as the maxillipeds, used as mouth parts, and five pairs of thoracic appendages located in the rear of the animal used for mobility purposes. Shrimp, lobsters and crabs make up this group.

What I will be dealing with, are the dreaded ISOPODS. Isopods are a diverse order of crustaceans that are cousins of the crab, shrimp and cray fish. Though hailing mainly from deeper waters of our oceans, their are both terrestrial and tropical shallow water species of isopods. Isopods have been a part of both terrestrial and water environments from the abyss to shallow regions for over 300 million years.

Isopods get their name from the Greek meaning ISO( similar or equal) and POD(foot) since they have the same number of legs and feet on both sides of their body carapace. They have fourteen pairs of legs and feet along their segmented body. These organisms differ from similar species of pods in that their appendages all perform the same function, unlike their relatives that can perform different functions with their various appendages such as walking, swimming and feeling. Their are three specific body parts that make up isopods; head, thorax and abdomen. They have a pair of antennae that assists these crustaceans with taste and smell.

The marine species of isopods MUST remain in water or they will die. Unlike their terrestrial brethren that have lungs to take in oxygen, marine isopods receive their oxygen in water through gill-like structures located at the base of their legs and do not have lungs.

They are normally a white, tan or cream color and can grow rather large, at least as far as pods are concerned, from 0.5mm to 500mm.

Their are various species of marine isopods that have a parasitic relationship with invertebrates and fish we maintain in a captive environment. To be more specific, roughly 10,000 species in 10 orders of pods. The entonicid species of isopods are associated with brachyuran and anomuran crabs and live within the hemocoel of the host crab. Their is also one species of etoniscid that has a parasitic relationship to snapping shrimp. Bopyridae isopods live in the gills or carapace of crabs and shrimp and their infestation will look like a bulge on their host. Dajidae species of isopods effect mysis, midwater shrimp and krill. These pods are hitchhiking parasites that attach themselves to the back of shrimp and look like a fleshy growth on the host shrimp. Cryptoniscinae species of pods run the gamut of infecting other species of isopods, amphipods, ostracods, mysids, barnacles and crustaceans.

One of the more problematic isopods that effects our marine life plagues our fish life. Yes, their are many isopods that are herbivorous in nature, and are characterized by their grinding mandibles(flat molars), whereas the carnivorous isopods that affect our fish contain cutting mandibles(blade like molars) that are responsible for cutting into the flesh of fish life. Flabellifera, epicaridea and gnathiidea species of isopods are the ones responsible for attacking our fish either through their attachment to gills, mouth regions and flesh in a parasitic nature. These pods attach to sick or injured fish as well as healthy specimens and if not handled appropriately and in a timely manner can kill any fish species.

It is critical to remove these as soon as possible from the infected fish to reduce the chances of infection or worse from taking place. Using tweezers is the best way of riding these pests from your prized collection of fish. Night time is the best time since your fish will be sluggish and less apt to retreat into the confines of your rock work causing a disaster area. Collecting the fish in a net to remove the fish from the water as quickly as possible is essential to reducing the stress placed on your infected fish species. Removing the isopod with tweezers and applying an iodine topical solution to the infected area will help to alleviate the chance of disease and infection taking place. The addition of medication to your main reef tank is ill advised as the potential for other problems arising is great that can effect various beneficial organisms and life. If the medication route is to be achieved, it is best to set up a quarantine tank separate from your main tank so that the potent medication will have no negative residual effect on other life forms. Once the pest isopods have fallen off, you can then place your fish back into the main tank.