Detritus worm outbreak

Thin white, beige or reddish bodies emerge from substrate, wave while anchored at one end or swim after cleaning or oxygen loss. A sudden mass exodus is more informative than numbers within substrate. Rotten-egg odour, black zones and distressed animals signal a more serious substrate problem.

‘Detritus worms’ mainly include small oligochaetes and other free-living worms processing organic matter in substrate and filters. A hidden population is normal; thousands on glass or in the water indicate abundant food and detritus or loss of substrate oxygen. They are usually a husbandry indicator rather than an animal disease.

Uneaten feed, faeces, dead leaves and clogged sponges increase resources. Compaction, poor flow and overload reduce oxygen in deeper layers and drive worms upward. Their increase can also follow predator removal or heavy fry feeding.

Escalate if mass emergence coincides with gasping, sulphurous odour, black substrate, ammonia or nitrite. Worms emerging from a host, lesions or weight loss require a separate parasitological diagnosis. With possible hydrogen sulphide, secure animals first and work in small sections.

Nematodes are smooth and whip in serpentine motion; planarians are flat and glide; leeches have suckers and shorten their bodies. Camallanus and other parasites emerge from a fish body or vent rather than freely from substrate. Segmentation, location and movement are more useful than colour.

Collect individuals separately from substrate and water and use magnification to look for segmentation and bristles. Test ammonia, nitrite and temperature and inspect behaviour near dawn when oxygen may be lowest. Examine substrate for compaction and dark pockets without disturbing everything at once.

Collect individuals separately from substrate and water and use magnification to look for segmentation and bristles. Test ammonia, nitrite and temperature and inspect behaviour near dawn when oxygen may be lowest. Examine substrate for compaction and dark pockets without disturbing everything at once.

Increase aeration and movement if worms emerge en masse, then reduce food and siphon accessible zones. Mechanically clean one filter section at a time while preserving biological media. Do not aggressively overturn a suspect deep substrate because it may release detritus and reduced compounds into the water.

Density falls with repeated siphoning, better flow distribution and proportionate feeding. A compromised substrate should be restored in sections or replaced under a plan protecting animals and biofilter; dewormers do not correct organic load and may trigger mass die-off. Track counts, odour and water readings together.

Regularly remove residue from dead zones, prevent the prefilter becoming a waste store and choose substrate grain compatible with planned maintenance. Feed according to actual consumption and avoid compressing substrate with décor. Night checks and post-cleaning observation establish the normal population.

Escalate if mass emergence coincides with gasping, sulphurous odour, black substrate, ammonia or nitrite. Worms emerging from a host, lesions or weight loss require a separate parasitological diagnosis. With possible hydrogen sulphide, secure animals first and work in small sections.