According to Customs Canada Website:

When importing an aquatic animal, an import permit will not be required when the owner can:

present proof of their identity and their ownership of the aquatic animal to the inspector at the point of entry into Canada
attest to the fact that the pet animal has not been taken to a show or display outside of Canada
keep the pet animal in their household aquarium
ensure the pet animal is not exposed to any aquatic animals other than those kept in the household, for one year following the importation
not import another pet aquatic animal as listed below for the period of 90 days after the importation
keep all records of the importation
- and -

The pet aquatic animal is one of the following susceptible species of finfish:

Barbonymus gonionotus
Carassius auratus
Colisa lalia
Danio rerio
Glossogobius giuris
Osphronemus goramy
Oxyeleotris marmorata
Poecilia reticulata
Puntius sophore
Symphysodon discus
Toxotes chatareus
Trichogaster pectoralis
Trichogaster trichopterus

Not sure you need anymore than that.

Yes, this is what I was going with. Only thing I wasnt sure was "present proof of their identity and their ownership" Receipt should be good enough for proof of ownership, part, but wasnt sure if they needed something specific for identity. If it says clowns on a receipt, would that be enough, or would they need Latin name, like it is listed in the susceptible list.

Thanks again for all the help

For the most part the border guards don't care. They are looking for alcohol and cigarettes that you may be smuggling into the country or something worse. You probably would be OK with the receipt stating "Aquarium Fish". Too much information sometimes confuses them and sends up red flags. However if you are concerned ask the retailer to include the Latin names.

I have crossed the border thousands and thousands of times. I purchase a load of stuff from BRS and elsewhere. Like I said before I just haven't brought fish over the border for many years because I see no purpose in it anymore as I can get whatever I want from a local retailer and I like to see what I buy before purchasing it. The prices for fish and corals in Seattle are more expensive then they sell here in Canada.

Just don't lie about what you have and what you are doing and you should be fine.

Thanks again for all the help and info. Good to know about prices as well. While I am nowhere close to being ready for fish (tank isnt even up and running yet) figured I would ask, as I was thinking about this for few weeks now.

fish from us
 

I have made numerous purchases from online retailers in us. you need AIRS report NOT CITES. airs, you have steps to follow...species, country etc and end use, which is listed as private aquarium. I have never had a problem returning to Canada, but DECLARE everything. I had a cites report and was told NO. need AIRS report which is straight forward. also inverts are on that list as well. if you cant find it on AIRS, it likely isn't allowed in. also imported coral frags and just declare, no problem. all thru pacific crossing...truck crossing

Thanks very much for this info. I took a quick look and it does look pretty straight forward. If I have any questions down the road, I shall ask at that time.