Can you obtain samples of th fish muscle which contain no parasite. If so, this is what you could try:-

Run the following samples on separate gels:

Sample 1. Sample of Fish protein alone ; there must be no parasite present. (Gel1)

Sample 2. Sample containing parasite which has the fish protein present. (Gel2)

Sample 3. Sample containing parasite which has fish present ( as in sample 2) and to which is added and mixed a quantity of fish protein alone ( sample 1). (Gel3)

In samples 1 and 2 make the quantities of proteins equal .

In sample 3 make the make the quantity of protein from the parasite plus fish sample (sample 2) equal to the quantity used in sample 2. Add a quantity of fish protein alone ( no parasite) at least equal to that in sample 1.

It is advisable to test different quantities of proteins but the quantity of parasite contains sample ( sample 2) MUST be the same in both sample 2 and sample 3. The quantity of pure fish protein in sample 3 should be varied but the total quantity of pure fish protein in sample 3 must be significantly hight than in sample 2.

Compare the spot patterns for the 3 gels . Spots in gel 3 that have greater intensity than spots in similar position on gels 1 and 2 are from fish proteins. The gel 3 spots with the same intensity and position as those in gel 2 are from the parasite.

You may need some tests to get the quantities to give useful patterns but the quantity of parasite proteins must be the same on both gels 2 and 3.

Peter Jackson that's a brilliant idea, sir. Thank you for your suggestion and surely I will try in the lab. Thanks again.