Hydrogen Sulfide (H2S) gas source, management and harmful effect of Hydrogen Sulfide (H2S) on Fish pond

Up to one third of the content of feed used in culture system may be indigestible. And 25% of the feed become wasted if sinking feed is used. That’s why massive gas problem specially Hydrogen Sulfide (H2S) gas occur at the middle of the culture stage. If we do not solve it fish suffer huge suffocation problem and mortality occur. We can easily understand by following diagram.

Hydrogen Sulfide Gas

H2S gas is soluble in water (4 grams per liter at 20*C) and is poisonous for any kind of fish. Less than 5.3 milligrams per liter will kill any culture species and less than 0.4 milligrams per liter has sub-lethal effects such as gill damage and stress. 

How H2S formed in pond bottom:

      

Ø  Deposit organic/inorganic debris in pond bottom ultimately turn aerobic ( O₂  rich condition) situation to anaerobic( O₂  depleted condition)  situation on that time Haterotropic bacteria Formed used organic debris as food and produce H₂S as byproduct. By following figure we can easily understand how much bottom deposition take place during culture period.

How to detect H₂S in pond environment

Ø  The  most common way to detect H2S is by a rotten egg odor

Ø  Bubble out of the water when bottom sediment is stirred-up

Ø  Using test kit

Affect of  H₂S on fish :

Ø The problem is that even at low pH levels H2S can become toxic because of high temperatures.

Ø  Create acid decomposition on water and soil, deplete oxygen.

Ø  Create high sludge on pond bottom and also create anaerobic condition which destroys beneficiary bacteria.

Ø   The moat destructive problem by H2S is gill damage 

Ø   Opercula movement and respiratory arrest. 

Ø   Poor feeding and an increased susceptibility to common diseases and parasites.

Death due to gas problem

Accepted hydrogen level in pond ecology is  .002pm

Easy technique to control Hydrogen Sulfide (H2S):

1. Flushed regularly and if possible make dry your pond at least one year to remove excess organic matter.
2.   Make a central toilet in pond bottom ( 2 feet depth a circular), used aerator so that organic debris cannot accumulate.
3.  Proper utilization of given feed so that no wastage happen
4.   Strictly avoided any kind of trees around the pond.
5. Used Ecotoxinil 5-7 gm/ Decimal water.
6.    Supper PS (Photosynthetic sulfur bacteria) -------- Early stage 2 L/Acre and middle stage 4 L/Acre.
7.       Ø  Zeolite or lime substances

Use any  kind of product which accelerate decomposition rate

Ammonia gas problem