Leto, at least before Late Night spawners didn't work in pools. People used fog emitters and entered codes to get the fish (sharks, or whatever) and bubbles and other effects. There are around 4000 codes for fog emitters (I haven't tried them). On the other hand, I build large fish tank using spawners for dynasty family (sharing stories/Stuckson immortal dynasty/page 9) and as I was told, only WA fish were in 3D, others were in 2D. I haven't tried others since I wanted those colorful Chinese fishes. For this thank I had to use both pool (for windows) and pond (for spawners to work), and some building cheats. I find walktrough on youtube. Haven't tried after getting Late Night, but spawning hasn't made any difference after reloading several times. They were always there.