If somehow, you could get the fish to your house without transporting it live between the river and your house, then the answer would be yes.
It is illegal to transport any live fish in B.C. This means any trout or salmon (or bass/pumpkinseed,etc) you catch at the river/lake are not legally allowed to be kept alive and transported to a tank/pond at your home. In your friends case, it is illegal to have baby chum, that he brought from the river, in his possession. The main goal of this rule is to stop illegal stockings of waterways.
That being said, if you bought these fish from a farm (and had permits), it would be legal. Private outfits will sell to people that have approval from the ministry to stock their pond (no chance of escape, adequate water conditions/supplies). I doubt they would sell to you to stock your tank, although places like Cabela's have them, so maybe it's possible.