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Gill filaments

Just like the lungs of humans, the gills of fishes are the sites where oxygen is absorbed and carbon dioxide is removed. In addition, the gills are responsible to a varying degree for regulation of the levels of various ions and the pH of the blood.

The gill filaments of bony fishes (also known as a primary lamellae) are complex structures which have a large surface area. Off each are numerous smaller secondary lamellae. Tiny blood capillaries flow through the secondary lamellae of each gill filament. The direction of blood flow is opposite to that of water flow. This ensures that as the blood flows along each secondary lamella, the water flowing beside it always has a higher oxygen concentration than that in the blood. In this way oxygen is taken up along the entire length of the secondary lamellae.

Active swimming fishes, such as the Blue Mackerel have well developed gill filaments to maximise the amount of oxygen that can be absorbed. Less active, bottom-dwelling fishes generally have much smaller gill filament volumes.

Not all fishes rely totally on their gills to breathe. Some species, especially when they are young, absorb a large proportion of their oxygen requirements through the skin. Others species have well developed lungs for breathing air, and will in fact drown if they do not have access to the surface.

References:

  1. Helfman G.S., Collette, B.B. & D.E. Facey. 1997. The Diversity of Fishes. Blackwell Science. Pp. 528.
  2. Lagler, K.F, J.E Bardach & Miller R.R. 1962. Ichthyology. John Wiley & sons. Pp. 545.
  3. Michael, S.W. 1998. Reef Fishes. Volume 1. A Guide to Their Identification, Behaviour, and Captive Care. Microcosm. Pp. 624.

Gill Disorders

Symptoms

 

Cause

 

Treatment and Links

A).   The gill filaments are light, having lost color

Has the pH changed? 
Is chlorine in the water? 
Is ammonia in the water?

Establish optimum water values.  Check pH, and Chlorine.  Use Aqua Gold.

 

 

 

 

 

The fish can be affected by a Kidney Disease

Treat fish with TMP Sulfa -or- Erythromycin.


B).   Small white objects (1 to 1.5mm) are attached to the gill filaments.  They hold very tightly

Gill Crustaceans

Treat the fish with  De-Los and Methylene Blue.


C).   Blood-red worms are visible on the inside surface of the operculum (gill plate), but usually only in pond fish

The fish are affected with blood worms (Philometra spp)

Treat the fish with De-Los


D).   Light flecks appear on the gills.  The gill filaments are necrotic at this spot

Eggs of the blood fluke Sanguinicola spp are involved.  If fungal hyphae are seen in the slides, then gill rot is involved

Treat with a bath in Acriflavine Neutral.


E).   Are the gills flecked with grey-white.  Do the filaments keep falling out?

Branchiomyces fungal gill rot

Treat with Forma-Green


F).   Cotton-like threads grow on the operculum (gill plate) or gill filaments

Saproglenia fungal infection

Treat with:   Forma-Green -or-  Acriflavine Neutral.


G).   Breathing is rapid, one or both opercula (gill plates) are open, and the fish rubs itself around the gills.  The fish hangs below the surface and gulps for air

The fish is affected with gill worms or gull flukes

Treat with: Praziquantel for marine fish or  De-Los for freshwater fish


H).   The gill filaments appear slightly cloudy, even whitish on the surfaces

Your fish are affected by a Protozoan Infection

Treat with:   Metronidazole and Methylene Blue.


I).   White dots appear on the gill filaments.  The dots measure 0.5mm in freshwater fish and to 1mm in marine fish

An Ichthyophthirius or Cryptocaryon disease is beginning to spread

Treat with:   Forma-Green -or- Copper Sulfate.  If marine cryptocaryon is resistant to the above treatments, use Quinine Sulfate


J).   Small, white modules appear on the gill filaments and cannot be removed

Most likely, sporozoan cysts

No suitable treatment known.


K).   The gill filaments swell up, becoming slimy and stick together

Chemical factors may be involved

Change the water and filter over fresh, activated charcoal.

 

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نشرت فى 13 فبراير 2009 بواسطة DrYasserIbrahem

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