"what's on my fish" ?

Fungus

What is a Fungus?

Fungi are a large group of organisms. Perhaps the most well known are yeasts, moulds, and mushrooms.

They are often mistaken for plants, but they are a completely separate group. Fungi are their own kingdom in taxonomic classifications.

Fungi do not Photosynthesise like plants; they consume food by absorbing dissolved Molecules. They secrete digestive enzymes to do this.

Most are incredibly small; some are even single-celled.

The three major groups are multicellular filamentous moulds, macroscopic filamentous Fungi (mushrooms), and single-celled microscopic yeasts.

The subdivisions of fungi are primarily based on their life cycles, structure, and type of spores. Spores are a reproductive unit that fungi use to spread into new areas. There are around 120,000 fungal species, but their biodiversity Is poorly understood.

Some scientists estimate that there could be up to 3.8 million species.

Many species are very resilient, which allows them to live in extreme habitats that are usually barren. This includes deserts, the deep sea, and areas with high levels of salt or ionizing radiation.

Most species are terrestrial, but some spend their whole life in water, or at least part of their lives.

These are the fungi that you might encounter as an aquarist. It’s most common for species to grow as structures called hyphae, which are string-like and can reach a few inches long.

New hyphae grow from existing hyphae to create a branching effect. This structure maximizes the surface area to volume ratio of the organism.

Fungi play a vital role in natural ecosystems. They are usually the primary decomposers in a food web. They break down organic matter, which is a key part of most nutrient cycles. However, they can cause health problems for your fish in an aquarium or pond.

It’s important to understand this kingdom of organisms so you can help your fish if they ever suffer from fungal diseases.