Microsporidiosis

Microsporidia are obligate intracellular spore forming parasites that are fungi or closely related to them.

They are common parasites in ornamental fish and are host and tissue specific, however some species can infect a broad range of fish.

The Microsporidia, Pseudoloma sp.,Heterosporis sp. and Pleistophora sp. are the most common infectious organism found in aquarium fish.

Pseudoloma neurophilia can infect a broad range of fish e.g. Neon tetra, Siamese fighting fish, Platy, Zebra fish. The parasite infects the central nervous system and muscle and may be associated with emaciation and skeletal deformities.

Heterosporis finki, another skeletal muscle infecting species, is similar to Pleistophora hyphessobryconis the causative agent of "Neon Tetra Disease".

Pleistophora hyphessobryconis targets the skeletal muscle of many aquarium fish e.g. barbs, rasboras, tetras, zebrafish etc., although the primary host is the Neon tetra. The affected fish exhibit massive infections in the skeletal muscle, fading with white patches under skin.

The first clinical sign that may indicate infested fish is colour loss of the red banding along the caudal peduncle.

The infective form of microsporidia is the resistant spore, which can persist in the environment for months.

Fish typically become infected by Pleistophora hyphessobryconis by ingesting spores released into the environment from necrotic muscle fibres of other infected fish or by scavenging dead, infected fish.

There is currently no effective treatments for neon tetra disease. Infected fish should be euthanized in order to prevent the infection from spreading to other fish in the aquarium.