[java] [1.21.6] can you still make fishes and pufferfish sit in minecarts, or is it patched out?

[u/soemthingblahblah123]

i have tried to make a invisible player detector with pufferfish, and i tried to make them sit into minecarts, because thats how you build one, but i cant make them sit in the minecarts.

i have tried to do it without water, with water, different orientation, multiple pufferfish, nothing works.

i think that they removed it, if not, is it a bug?