Yea. I agree with you Tom. This does not make any since at all. I too had fish in an aquarium and a pond and realized later that they were not spawning anymore in the oceans. I guess until more complaints are made, the "Mods" are not going to do anything about it.
The answer to this issue is don't release any fish from a bucket unless you use less then 15 of them. Anymore than that will stop all spawning of animals in the oceans. This includes dolphins, squid and fish. Apparently this is " Works as Intended".
I reported this too, but they closed it. It takes around 15 or 16 released fish to make this happen. You can kill the fish down to under 15 and the ocean mobs will start spawning again.
So... 16 released fish in a bucket in a freshly generated world that stops all ocean mobs from spawning is as intended. Sound like a bug to me. Very frustrating and should not be a feature if that is the case.
Thanks Torabi for looking into this.
I too did not think they were supposed to count towards the mob count. I thought they were considered a named mob. I started naming the fish in a bucket at first, which gives the same results btw, then I did them without naming them as the wiki states that you do not need too.