It is only in Harvest Moon Boy & Girl that I truly have begun to appreciate the beauty of the Fish Pond. Although you have a Fish Pond in Friends of Mineral Town and More Friends of Mineral Town, it really is not particularly significant in terms of gameplay. There is an error in fact in one of those two games that causes the Pond to hand you small fish instead of large fish and vice versa... There is no option to buy Fish Food at the Supermarket, however, and there are better ways to make money (such as fishing during festivals and exploiting the Horse Races to fill your basket with brooches).
You have a Pond in Harvest Moon DS and Harvest Moon Cute DS but it is an upgrade and the reason why you need to order it is not for fish but, as in 'A Wonderful Life' and 'Another Wonderful Life', so as to entice ducks to the farm. In HM DS and Cute DS, you actually must purchase the ducks from Popuri but she will not offer them until the Pond is built. Another reason for the Pond in HM DS is to persuade Leia to marry you... if you do not have a Pond, she will not have an appropriate place to live on your farm. Apparently, as a potential spouse, she sets her sights higher than the bathtub in which she is content to spend her days in Daryl's Basement... YOUR bathroom simply won't do!
Of course, if you had been able to persuade Leia to live in your Bathroom, you never would SEE her again, as all activities that occur in that mysterious chamber (and the Toilet) are hidden from players. Personally, I am glad that we do not have to view our characters on the toilet. In the Sims, for example, far too much time is spent in the latrine, with options to read a paper, play video games and many more. Mercifully, Harvest Moon does not subject its players to this sort of invasion of privacy...
The subject of this article is NOT the Bathroom but the Fish Pond. If you place two Large Fish in the Fish Pond and ply them with Fish Food daily, they may spawn others. Small and Medium Fish placed in the Pond will grow into Large Fish.
Now THIS is a Fish Pond that actually has some uses... Oddly enough, the first two fish I caught in Harvest Moon Boy & Girl were Large Fish. Despite my abject poverty at the beginning of Spring, I tossed them into the Fish Pond and began to feed them.
Sad to say, I ultimately sold them in order to be able to afford a larger rucksack and then was cross with myself for doing so... Meanwhile, I had caught a few small fish and one or two medium fish. The total number of fish in my Fish Pond at the end of Spring was 9, none of whom were Large Fish, sadly.
Two days ago, the total remained 9... Today, I saw that the total had jumped to 16. Going to the Pond, I removed a Fish and saw that it was Large. As I had no large fish in the pond after selling my 2 initial large Fish, some of the others must have grown to full size!
This sort of small detail delights me, even if it is not worth much in financial terms. Again, it makes all the hard work and effort worthwhile...