What do you want to do with the fish: ecological, behavioural, physiological, biochemical, toxicological or other studies? Which species can you choose from?

hi Joacim ,

thanks for your rply..

i am planning to go with biochemical, immunological studies...haven't fixed with species..planning for fresh water fishes...

Julian,

that was my plan also at d beginning, i tried it (Danio rerio) for blood, it doesn't seem to yield more blood for me..drawing blood from it strains it a lot..

Perhaps one of the tilapia species may be an option? I have not worked with them myself, but they are commercial aquaculture species, so there are probably good and validated methods for many types of sampling. And the results you get may be interesting for a lot of other researchers (which is good for collecting citations of your work :) )

Julian,

thanku so much.. i am trying now with carassius auratus only..ya. i need them alive after drawing blood. it's also the same in drawing blood .. iam getting only few microliters but that too getting clotted bfre entering syringe(even with heparinised needle)..

and thanku so much for ur reply..

Joacim ,

thanku so much..that's an good idea ..i'll try out whether i can get aqualculture species in my area..

Since you ask for criterias for choosing, here are some that you may want to consider:

* Size

* Life span (how old do they get?)

* Availability (how easy is it to get more of them in the size and age that you want?)

* Food (what do they eat?)

* Housing:

- How easy are they to keep alive in your research facility (e.g. are your tanks big enough)?

- What water quality and temperatures do you need to house it?

- Can you house them in groups (and how big groups can you have) or are they aggressive to each other?

* Handling (are they sensitive to stress when being handled?)

* How much variation do they have in the parameters you will measure (important for choosing sample size)

* Do males and females differ (if so, what should you choose males or females for your experiments)?

* Disease (are they prone to get infected and can you treat infections?)

* How many standardized methods are available and validated?

* How many other people work with the species (scientific and commercial interest)?

* Is the work you want to do already done in this species?

...and there are probably many more criterias...

What now is known as the "Krogh's principle", but already formulated in a similar way by Claude Bernard in 1965 is that "for such a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied."

What August Krogh was pointing out is that for each specific research question, there is a species which is best suited for research aimed at solving the question.

You seem to start in the wrong end by first trying to choose a species. You first need to define your research questions carefully, then choose the species best suited for research in that area.

Also the word "model" is being overused - almost every species appears to be a "model" species these days. What "model species" refers to is a species which represents a large group of organisms so that data obtained from the "model species" can be useful for explaining function in other species. For fish, the zebrafish has become a model species for several reasons, a major one being that the genome is known. However, on has to realize that even a model species has its place in the phylogenetic tree of evolution, and is thus only "a model" for some species, not others.

Björnsson,

Thanku so much for your kind explanation... Ok.. I should change my approach and turn over.. thanku so much.. mam..

I am involved in immunological studies. where i may go for expression studies, and blood parameters, can you help me out in some in suggesting some species mam.. or should i be more narrowing down?

Fish immunology is not my field of expertise, and anyway, your research definition is too vague to pinpoint a single species as the best one to use.

However, being pragmatic one can say that there are two principal sides to research; fundamental and applied.

If you want to focus on fundamental mechanisms to advance the general knowledge in the field of fish immunology, you're probably best off by choosing a species on which fair amount of immunological research has already been carried out. This way, you can analyze the available research literature to identify unsolved questions.

If you rather want to focus on the applied aspects - knowledge on immunology is of great importance for the advancement of aquaculture, then you should choose species which is either important for aquaculture in your area (this usually allows good access to the species for research purposes) or is of potential interest for future aquaculture.

Thanku .. So much..i should shape my idea.. Much more..