You could offer to remove and fill the ponds for any buyers, at your cost. If I were going to buy it I would feel much better knowing that was a possibility. I have small children so I would not even consider a house with ponds, but I would if they offered to fill it if I wanted to.

no.I have a pond,,my house is on the market,,the people they are showing the house to like the pond

Those types of ponds are a personal thing. Some folks like fish and some don't. So consider what the majority would be looking for and give it to them. If that means taking them out and making it just yard, then I'd do it. And save face with your Realtor having to tell you that.

It will certainly put off buyers with small children because of the safety aspect.

We very nearly didn't buy this house because of the 12ft x 8ft x 3ft high (6ft deep) pond that is in the garden. Previous owner was a koi fanatic. We still have it (just with goldfish) until the wife figures out how she wants the garden. This means we'll probably have it forever *sigh*

No, but it might with people who have small children.