Fly problem

Dallas Weaver deweaver at
Mon Jul 7 10:09:36 EST 2003

Adding to Jen Matthews comments :

If they are sludge fly's, you may be better off leaving them alone as the 
larva are cleaning your system and don't impact zebra fish.  If you 
eliminate the sludge flys and don't eliminate or continuously clean the 
areas where they are now growing, you can grow organisms to 
consume that organic material that are more problematic with respect 
to your zebra fish health (opportunistic pathogenic bacteria and 

The other option is to spend more time cleaning. However, always 
keep in mind that all recycle systems are really full ecologies and the 
fly's are just another component.  


Note: Higher performance biofilter system leave less BOD in the water
and seem to prevent sludge fly problems.

> Hi Maggie,
> Is your problem with the common house fly (Musca domestica) or with
> one of the many aquatic or semiaquatic species of flies. If you can
> identify the type of fly you are dealing with, you may be able to
> better direct your control efforts. One common fly species found
> near aquatic environments is the moth fly or drain fly. I've
> included some information below. good luck, -Jen  
> Moth Flies Moth flies (Subfamily Psychdidae) have many names 
> including drain flies, filter flies and sewage flies. The widespread
> subfamily Psychdidae contains four genera with over 50 aquatic and
> semiaquatic species in North America. Adults range in size from 1.6
> =96 6.4 mm. They may be yellow to brown to black in color. The
> adults are hairy and hold their wings roof-like over their bodies
> when resting. During daylight, they will often be found resting on
> walls near drains. They are most active during the evening and may
> be attracted to light. Moth flies do not bite.  
> Moth fly larvae are rarely seen because they live in drain areas or
> other protected locations. Most larvae are cylindrical or slightly
> flattened and=
> are usually less than 5 mm in length. The larvae entirely lack
> prolegs and body segments are usually subdivided into annuli. The
> thorax is not distinctly thicker than rest of body. They often have
> a pale underside with a darker head and tail, and dark bands (dorsal
> plates) across their backs.  
> Both larvae and adult forms feed on microorganisms, fine detritus
> and other decaying material. Adult female moth flies most often lay
> their eggs in masses on the surface of gelatinous films found in
> drains and sewers or other dark, moist areas. Adults live about two
> weeks. Moth flies are not strong fliers and cannot fly long
> distances. Most infestations originate in the area where the adults
> are found. Any aerosol or spray insecticide will easily kill the
> adults but these are not=
> recommended in aquaculture facilities. For effective and long-term
> control, the breeding sites must be found and removed. Inspect
> drains and other moist areas for potential breeding sites. Drains
> can often be cleaned with over-the-counter cleaners or diluted
> bleach followed by a hot water rinse. If this is not successful,
> mechanical cleaning with a sti= ff brush may be required to remove
> any film lining the drain.  
> Jennifer L. Matthews, DVM, PhD
> Zebrafish International Resource Center
> 5274 University of Oregon
> Eugene, OR 97403-5274     <(()><
> (541) 346-6028 ext. 14             <(()><
> Fax (541) 346-6151
> jmatthews at
> On Tuesday, July 1, 2003, at 12:02  PM, Mctighe, Maggie S wrote:
>>One of our investigators has a large room with 10 racks of zebra
>>fish. The racks are 5 years old and are marine biotech shelf
>>overflow design. He has bug zappers in the room, and the room is in
>>a university basement.  There are no open windows anywhere, but 
>>have a fly problem.  Need suggestions for getting rid of flies.
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