Should I set up an underground fishing area?
I have a surface pond, one level above ground, close to.my fortress. There are 8-10 squares of water with level up to 3.
Should I somehow dig a sufficiently deep pool under this, with a one level gap, and the breech the pool to fill up my artificial pool?
What is the mechanism for this?
Moving the water will displace the immediate population, but ponds rivers and cavern lakes (not to mention the ocean) have their own spawning fish and it works best when it is done naturally. If the biome allows it sometimes catchable toads will spawn in waterlogged not-pond tiles, as long as its the rough area any fish you relocate to a custom pond they'll survive in or near the area they were took from.
Fish in the caverns require the same biome as where cavern fish are naturally found to do this. The fishery job to 'catch a live fish' with a animal-trap cage (the one reserved for vermin) will safely take it out of that enviroment, where you can deposit it where you like, such as a aquarium made out of glass filled with water for dwarves to admire or empty it into a pond (alternative pit in the 'i' screen)
Very simply though, anywhere where you can see vermin-fish, you can just mark a little 'i' fishing zone there to direct dwarves where you want the to go, including anywhere specially built by yourself by redirecting or pumping water in with screw pumps.
Can I breed cave lobster and cave fish? I brought some with me.
My dogs died before breeding. Sigh...
The cave lobster and the fish are already gutted and prepared for consumption, though you can catch fish in the caverns if they have water around, most above-ground fish will probably need a river nearby as 'stagnant pools' that refill with rain do not restock themselves after a deep freeze (turning the water solid in winter to mineable ice) and can be overfished. Rivers and oceans have much higher fish populations that'll probably never run out without many years of freezing solid.
Not to worry, you can obtain more dogs (and some other animals) from dwarven merchants by waiting or asking for some in a trade agreement, they're not too hard to pasture close together to breed because of large litter sizes you'll soon have lots of puppies. You will need a broker and preferably some supplies to barter with by the time the traders arrive in Autumn each year.
If they arent segregated by name on the list like dogs are, you can look at the other animals in the 'pets' section to get a idea of the ordering. Rams and Ewes (sheep) for example, take note of which one is above the other on the list as this is how the gendering is ordered.