Since laws are not written about impossibilities, it is legal to marry amphibians in any state. However, it is up to the participants to figure out how that might be done.
You click on Hunt a Critter and then click the pets that show on that page, there are 30 each time I believe. Finding the hunted creature is completely random, you may find it on the 10th click, or...
In the original Impossible Creatures game (without expansion packs), there are a total of 51 units, or creatures (though the main website claims to have 50 units), including:
33 land units
12...