If not, there is always the option of making War sea kittens(Carps), to fill your moats with.
Have you ever tried getting dwarves to cage, let alone tame, or try and train the carp, in the kennels, on land?
There's no chance of this happen for multiple reasons:
1. I'm never going to attempt to use the watery menace for my own purposes
2. I've killed all the carp
3. Carp drown in air
4. I use magma moats
5. I've accidentally filled the river with magma anyway