Fish not spawning, even in new worlds

No fish are spawning in any world, even brand new ones. The only fish in my worlds are ones that were spawned in before snapshot 19w13a. To test this, I created a fresh new world in 19w13b, flew to the nearby ocean, waited a few minutes to give ample time for fish to spawn, then ran the command /tp @e[type=minecraft:cod] <username>, which would teleport any cod loaded in to me. This command was unable to locate any cod. I have repeated this test in multiple locations, and with salmon over rivers, but no entity is ever found. Dolphins, squid, and turtles all appear to still spawn normally.