Swimming in lake with fish allergy

[cuvee1812]

Just wondering if anyone in the group with a fish allergy has experienced an issue swimming in lakes?

My 7 yo son has a fish allergy.  We were at a cottage on a lake.  He went swimming, he LOVES swimming.  But, as I'm sure is common with young children, he took in some lake water.  Within about 15 minutes, I noticed he was swallowing hard, his breathing was just a bit off, and he complained his throat was sore.  His fish allergy is anaphylactic.  He said his tongue felt fine and he had no swelling of his lips (as he did when we discovered his allergy due to a reaction to eating fish). 

While there are fish in the lake, my inclination would be to believe that any possible concentration of fish protein in the water would have to be VERY low... but, I do suppose it would still be possible???

Has anyone else with a fish allergy ever had a reaction after swimming in a lake?  Or the ocean?

TIA,
Tessa

[rebekahc]

My DD has a shellfish allergy and has reacted to swimming in the ocean.  She's also reacted to putting two fingers in the touch tank at the aquarium.  But, as far as I know that's VERY rare.