are fish in centrepieces a thing? or is that against most venue rules and regulations

Hello,

It depends on what the theme of your wedding is. I have seen reception venues / restaurants, decorated in a marine / beach theme.

You can have little gold fish inside large brandy glass vases, or tall cylander vases.

Of course we would have to check with the reception venue and comply with their rules and regulations. But yes it can certainly be done.

It is a thing ~ you would have to check with the venue on the rules and regulations.  There is a company in Sydney who specialise in these ~ they supply the aquariums and the fish as well as staff to ensure all is handled well.