Parasites in general

Unfortunately, many pond owners will sooner or later encounter disease symptoms in their ponds. The causes of pond fish disease were described in a previous article ( disease-causing agents in the pond ). In this article, we will divide the various parasites that can cause disease symptoms into several main groups. In later articles, we will delve deeper into the representatives within these main groups.

Know your enemy!

It's crucial to gather as much information as possible about the pathogen. "Know your enemy," I often emphasize in my courses. After all, the better you know your enemy, the easier it becomes to combat it effectively. By attacking the parasite at its weakest point, you can prevent the use of harmful "medicines" (see article). Keeping medication to a minimum will have the least disastrous consequences for your beloved pond inhabitants.

Main groups of parasites

To get to know our enemies well, I'll first roughly classify them. In the literature, all living organisms are classified into "Domains," "Kingdoms," "Phylums," "Classes," "Orders," "Families," "Genesis," and "Species." That's a bit much for our purposes. Therefore, I'll limit myself to "Main Groups," "Subgroups," and "Species," with separate articles for the different "species"—think, for example, of "skin worms" or "white spot worms." Incidentally, not all species that fall under the main and subgroups are parasitic. The classification into main and subgroups is as follows:

Worm-like

This concerns a group of animal, multicellular organisms in which both sexual and asexual reproduction can occur, and in which some are viviparous and some are oviparous. The following subgroups are distinguished:

Nematodes (annelid or threadworms)
Trematodes (flatworms)
Cestodes (tapeworms)

Examples: Skin worms, Gill worms, leeches, camallanus.

Crustaceans

These are animal, multicellular organisms that reproduce sexually and lay eggs. Lobsters are arthropods (which also includes insects) and have an exoskeleton (cuticle) that doesn't grow, requiring them to molt regularly.

Examples: Anchor worm, Carp louse.

Protozoa

These are animal, unicellular organisms that reproduce asexually through cell division (sometimes preceded by cyst formation). Subgroups:

Ciliates (pennants)
Flagellates

Examples: Costia, Trichodina, White Spot.

Bacteria

These are single-celled organisms that reproduce asexually through cell division. Subgroups:

Bacteria can be grouped in many ways, but this adds nothing to our specific purpose, so I will leave it out.

Examples: Flexibacter Colomnaris, Pseudomonas, Aeronomas Punctata.

Fungi

These are multicellular organisms that can be viewed as a plant, without chlorophyll.

Examples: Saprolegnia, Branchiomyces, Dermocystidium.

Viruses

Viruses are not made up of cells. A virus (particle) is nothing more than a strand of DNA or RNA surrounded by a protein coat. Viruses are always parasitic.