What are loach fleas called? - briefly
The parasite commonly referred to as a loach flea is the ciliated protozoan Trichodina. It attaches to the skin and gills of loaches, causing irritation and potential disease.
What are loach fleas called? - in detail
The parasite most frequently referred to as a “loach flea” is the ciliate Trichodina loachii. It belongs to the genus Trichodina, a group of microscopic, dorsoventrally flattened organisms that attach to the skin, gills, and fins of freshwater fish, especially loaches (family Cobitidae).
Morphology
- Cells are 30–80 µm long, oval‑shaped, and covered by a crown of denticulated stalks (the “operculum”).
- The stalks terminate in adhesive discs that allow the organism to cling to host tissue even under strong water flow.
- A conspicuous cytostome (mouth‑like opening) sits at the cell’s anterior pole, used for ingesting epithelial cells and mucus.
Life cycle
- Attachment phase – free‑swimming trophonts locate a host by chemotaxis, then embed their adhesive discs into the epidermis.
- Reproductive phase – trophonts mature into sessile forms that undergo binary fission, producing 2–4 daughter cells per division.
- Dispersal phase – when environmental conditions become unfavorable (e.g., temperature rise, low oxygen), the organism detaches, becoming a motile tomite that seeks new hosts.
Pathogenic effects
- Mechanical irritation of the skin and gill epithelium.
- Localized hyperplasia and mucus hypersecretion.
- In severe infestations, respiratory distress due to gill damage and secondary bacterial infection.
Diagnosis
- Microscopic examination of skin scrapes or gill imprints reveals the characteristic opercular crown.
- Quantitative counts (cells per mm²) help assess infestation severity.
Control measures
- Quarantine new fish for at least 30 days; treat water with diluted formalin (25 mg L⁻¹) or hydrogen peroxide (150 mg L⁻¹) for 30 minutes to kill free‑swimming stages.
- Environmental management: maintain stable temperature (22–26 °C), high dissolved oxygen, and regular water changes to reduce stress‑induced susceptibility.
- Chemical therapy: copper‑based salts (0.2–0.5 ppm) can suppress attachment, but must be used cautiously to avoid toxicity to sensitive loach species.
- Biological approach: introduce clean, well‑conditioned substrate and avoid overcrowding, limiting opportunities for the parasite to spread.
Research notes
- Molecular analyses of the SSU rRNA gene confirm that T. loachii clusters with other fish‑associated Trichodina species, indicating a host‑specific lineage.
- Recent studies suggest that the parasite’s adhesive disc proteins share homology with those of other peritrich ciliates, offering potential targets for novel anti‑parasitic compounds.
In summary, the organism colloquially called a loach flea is the ciliate Trichodina loachii, a microscopic ectoparasite that adheres to loach skin and gills, reproduces by binary fission, and can cause significant pathology if left uncontrolled. Effective management relies on early detection, quarantine, water quality optimization, and appropriate chemical or biological interventions.