@ Satish, please have a look of the attached file that may be useful to you.

Hi Satish, There are lot of research happening on fishes all over the world and in our country too. So, lot of literature available on this.

But, I can give you one major point that acclimatization may be the problem. Especially, you mentioned small fishes, I think these might be fingerlings (small fishes). It is very difficult for the fingerlings to survive in just totally different conditions.

So, what you can do is to make them acclimatize properly. Next time, when you collect fishes bring some water from the same water body and keep them in that water for some time and don't change the whole water at once instead do it step wise, like change a part of it with fresh water according to the need.

I am attaching one pdf file about fish sampling, may it will be helpful for you..........

I think it will work, you can try.

Kindly inform if you will get success by this method.

Thank you,

Good luck

Collect as normal and freeze in foil, do not use formalin.

If you want to keep them alive you MUST add an air pump!

Dear Satish,

If you are doing toxicity study in lab , i think it should be as per OECD guideline .

the guideline recommends few specific species along with the age and size of the fish to be used..

My suggestion is ..better to get the required juvanile fish from local fishery department or commercial vendors, since getting required size juvanile fish from natural pond is difficult meanwhile you need to characterize the fish for species confirmation.

Please refer OECD Test Guideline for performing Fish Toxicity Test.

Few Points you may consider -

1. The water quality should mimic its natural water to certain possible extent for few days before commencing trial . this will helps fish to acclimatize gradually to new environment.

2.You need to ensure dissolved oxygen in water you maintained in lab aquarium. use commercially available air pumps for the same.

2. Do Not over feed the fishes .

Dear Satish Sir,

fishes from CAPTIVE BRED ENVIRONMENTS have a greater chance of being disease free and proper nutritional growth. So it is always better to collect fishes for study from such captive bred centres than from the wild.

Such fishes once collected should be handed minimum and quickly transported to the laboratory in oxygen filled large Polythene bags with adequate water and fishes in it.

once reached the laboratory, a pre-setup of aquarium tanks filled with clean, non-chlorinated water and added oxygen pipes in it, should be kept ready depending upon the density of fishes collected from the captive bred centre to be stored in the tanks.

the fishes should not be released directly in tanks, as the temperature and physico-chemical properties of water in tank and in the polythene bag may be different, and such sudden changes in environment can shock the fishes and chances are that they might not survive the stress.

so instead, the polythene bag along with fishes, itself should be partially inserted in the aquarium water ( make sure to clean the polythene bag from outside under the tap if it is dusty or dirty before inserting in water tank ) and kept until 15 to 20 minutes so that the temperature in both environments is equilibrated.

now open the polythene bag mouth and add a few mugs of water from tank into it and let the fish stabilized for some more time in the mixture of old and new water.

once stabilized, you can now take out the fishes with the help of a small hand net, dip them in 10 mg/l KMnO4 solution for 5-10 minutes and transfer them to the new tank.

Avoid feeding the fishes till the next 24 hours in tank and let them to acclimatize properly in their new environment.

maintain proper water quality and water recirculation in the tank till the end of all your experiments on fishes.

Thus by following these protocols you can ensure that most fishes stay alive and healthy throughout your experimental requirements.

If you start working with fish for tox tests I recommend Guppy (Poecilia reticulata). They are extremely resilient to handling, very sensitive to toxicants and easy to grow. OECD guidelines indeed.

James W Everts Nagesh Birajdar Rajesh Rangappa Lee A. Fitzgerald Deepak K. Goyal J. C. Tarafdar and everyone thank you for your suggestions. It would be very helpful for me in conducting the experiments.

Thanks again

Dear sir,

Please check the below link http://www.fao.org/tempref/FI/CDrom/FAO_Training/FAO_Training/General/x6709e/x6709e11.htm

Very instructive.